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( x + 5 ) ( x 5 ) = x 2 25 ( x + 11 ) ( x 11 ) = x 2 121 ( 2 x + 3 ) ( 2 x 3 ) = 4 x 2 9

Because the sign changes in the second binomial, the outer and inner terms cancel each other out, and we are left only with the square of the first term minus the square of the last term.

Is there a special form for the sum of squares?

No. The difference of squares occurs because the opposite signs of the binomials cause the middle terms to disappear. There are no two binomials that multiply to equal a sum of squares.

Difference of squares

When a binomial is multiplied by a binomial with the same terms separated by the opposite sign, the result is the square of the first term minus the square of the last term.

( a + b ) ( a b ) = a 2 b 2

Given a binomial multiplied by a binomial with the same terms but the opposite sign, find the difference of squares.

  1. Square the first term of the binomials.
  2. Square the last term of the binomials.
  3. Subtract the square of the last term from the square of the first term.

Multiplying binomials resulting in a difference of squares

Multiply ( 9 x + 4 ) ( 9 x 4 ) .

Square the first term to get ( 9 x ) 2 = 81 x 2 . Square the last term to get 4 2 = 16. Subtract the square of the last term from the square of the first term to find the product of 81 x 2 16.

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Multiply ( 2 x + 7 ) ( 2 x 7 ) .

4 x 2 −49

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Performing operations with polynomials of several variables

We have looked at polynomials containing only one variable. However, a polynomial can contain several variables. All of the same rules apply when working with polynomials containing several variables. Consider an example:

( a + 2 b ) ( 4 a b c ) a ( 4 a b c ) + 2 b ( 4 a b c ) Use the distributive property . 4 a 2 a b a c + 8 a b 2 b 2 2 b c Multiply . 4 a 2 + ( a b + 8 a b ) a c 2 b 2 2 b c Combine like terms . 4 a 2 + 7 a b a c 2 b c 2 b 2 Simplify .

Multiplying polynomials containing several variables

Multiply ( x + 4 ) ( 3 x 2 y + 5 ) .

Follow the same steps that we used to multiply polynomials containing only one variable.

x ( 3 x 2 y + 5 ) + 4 ( 3 x 2 y + 5 )   Use the distributive property . 3 x 2 2 x y + 5 x + 12 x 8 y + 20 Multiply . 3 x 2 2 x y + ( 5 x + 12 x ) 8 y + 20 Combine like terms . 3 x 2 2 x y + 17 x 8 y + 20   Simplify .
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Multiply ( 3 x 1 ) ( 2 x + 7 y 9 ) .

6 x 2 + 21 x y −29 x −7 y + 9

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Access these online resources for additional instruction and practice with polynomials.

Key equations

perfect square trinomial ( x + a ) 2 = ( x + a ) ( x + a ) = x 2 + 2 a x + a 2
difference of squares ( a + b ) ( a b ) = a 2 b 2

Key concepts

  • A polynomial is a sum of terms each consisting of a variable raised to a non-negative integer power. The degree is the highest power of the variable that occurs in the polynomial. The leading term is the term containing the highest degree, and the leading coefficient is the coefficient of that term. See [link] .
  • We can add and subtract polynomials by combining like terms. See [link] and [link] .
  • To multiply polynomials, use the distributive property to multiply each term in the first polynomial by each term in the second. Then add the products. See [link] .
  • FOIL (First, Outer, Inner, Last) is a shortcut that can be used to multiply binomials. See [link] .
  • Perfect square trinomials and difference of squares are special products. See [link] and [link] .
  • Follow the same rules to work with polynomials containing several variables. See [link] .

Section exercises

Verbal

Evaluate the following statement: The degree of a polynomial in standard form is the exponent of the leading term. Explain why the statement is true or false.

The statement is true. In standard form, the polynomial with the highest value exponent is placed first and is the leading term. The degree of a polynomial is the value of the highest exponent, which in standard form is also the exponent of the leading term.

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Many times, multiplying two binomials with two variables results in a trinomial. This is not the case when there is a difference of two squares. Explain why the product in this case is also a binomial.

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You can multiply polynomials with any number of terms and any number of variables using four basic steps over and over until you reach the expanded polynomial. What are the four steps?

Use the distributive property, multiply, combine like terms, and simplify.

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State whether the following statement is true and explain why or why not: A trinomial is always a higher degree than a monomial.

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Algebraic

For the following exercises, identify the degree of the polynomial.

14 m 3 + m 2 16 m + 8

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200 p 30 p 2 m + 40 m 3

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6 y 4 y 5 + 3 y 4

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For the following exercises, find the sum or difference.

( 12 x 2 + 3 x ) ( 8 x 2 −19 )

4 x 2 + 3 x + 19

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( 4 z 3 + 8 z 2 z ) + ( −2 z 2 + z + 6 )

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( 6 w 2 + 24 w + 24 ) ( 3 w 2 6 w + 3 )

3 w 2 + 30 w + 21

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( 7 a 3 + 6 a 2 4 a 13 ) + ( 3 a 3 4 a 2 + 6 a + 17 )

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( 11 b 4 6 b 3 + 18 b 2 4 b + 8 ) ( 3 b 3 + 6 b 2 + 3 b )

11 b 4 −9 b 3 + 12 b 2 −7 b + 8

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( 49 p 2 25 ) + ( 16 p 4 32 p 2 + 16 )

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For the following exercises, find the product.

( 4 x + 2 ) ( 6 x 4 )

24 x 2 −4 x −8

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( 14 c 2 + 4 c ) ( 2 c 2 3 c )

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( 6 b 2 6 ) ( 4 b 2 4 )

24 b 4 −48 b 2 + 24

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( 3 d 5 ) ( 2 d + 9 )

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( 9 v 11 ) ( 11 v 9 )

99 v 2 −202 v + 99

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( 4 t 2 + 7 t ) ( −3 t 2 + 4 )

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( 8 n 4 ) ( n 2 + 9 )

8 n 3 −4 n 2 + 72 n −36

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For the following exercises, expand the binomial.

( 3 y 7 ) 2

9 y 2 −42 y + 49

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( 4 p + 9 ) 2

16 p 2 + 72 p + 81

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( 3 y 6 ) 2

9 y 2 −36 y + 36

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For the following exercises, multiply the binomials.

( 4 c + 1 ) ( 4 c 1 )

16 c 2 −1

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( 9 a 4 ) ( 9 a + 4 )

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( 15 n 6 ) ( 15 n + 6 )

225 n 2 −36

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( 25 b + 2 ) ( 25 b 2 )

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( 4 + 4 m ) ( 4 4 m )

−16 m 2 + 16

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( 14 p + 7 ) ( 14 p 7 )

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( 11 q 10 ) ( 11 q + 10 )

121 q 2 −100

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For the following exercises, multiply the polynomials.

( 2 x 2 + 2 x + 1 ) ( 4 x 1 )

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( 4 t 2 + t 7 ) ( 4 t 2 1 )

16 t 4 + 4 t 3 −32 t 2 t + 7

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( x 1 ) ( x 2 2 x + 1 )

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( y 2 ) ( y 2 4 y 9 )

y 3 −6 y 2 y + 18

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( 6 k 5 ) ( 6 k 2 + 5 k 1 )

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( 3 p 2 + 2 p 10 ) ( p 1 )

3 p 3 p 2 −12 p + 10

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( 4 m 13 ) ( 2 m 2 7 m + 9 )

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( a + b ) ( a b )

a 2 b 2

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( 4 x 6 y ) ( 6 x 4 y )

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( 4 t 5 u ) 2

16 t 2 −40 t u + 25 u 2

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( 9 m + 4 n 1 ) ( 2 m + 8 )

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( 4 t x ) ( t x + 1 )

4 t 2 + x 2 + 4 t −5 t x x

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( b 2 1 ) ( a 2 + 2 a b + b 2 )

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( 4 r d ) ( 6 r + 7 d )

24 r 2 + 22 r d −7 d 2

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( x + y ) ( x 2 x y + y 2 )

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Real-world applications

A developer wants to purchase a plot of land to build a house. The area of the plot can be described by the following expression: ( 4 x + 1 ) ( 8 x 3 ) where x is measured in meters. Multiply the binomials to find the area of the plot in standard form.

32 x 2 −4 x −3 m 2

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A prospective buyer wants to know how much grain a specific silo can hold. The area of the floor of the silo is ( 2 x + 9 ) 2 . The height of the silo is 10 x + 10 , where x is measured in feet. Expand the square and multiply by the height to find the expression that shows how much grain the silo can hold.

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Extensions

For the following exercises, perform the given operations.

( 4 t 7 ) 2 ( 2 t + 1 ) ( 4 t 2 + 2 t + 11 )

32 t 3 100 t 2 + 40 t + 38

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( 3 b + 6 ) ( 3 b 6 ) ( 9 b 2 36 )

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( a 2 + 4 a c + 4 c 2 ) ( a 2 4 c 2 )

a 4 + 4 a 3 c −16 a c 3 −16 c 4

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Questions & Answers

Three charges q_{1}=+3\mu C, q_{2}=+6\mu C and q_{3}=+8\mu C are located at (2,0)m (0,0)m and (0,3) coordinates respectively. Find the magnitude and direction acted upon q_{2} by the two other charges.Draw the correct graphical illustration of the problem above showing the direction of all forces.
Kate Reply
To solve this problem, we need to first find the net force acting on charge q_{2}. The magnitude of the force exerted by q_{1} on q_{2} is given by F=\frac{kq_{1}q_{2}}{r^{2}} where k is the Coulomb constant, q_{1} and q_{2} are the charges of the particles, and r is the distance between them.
Muhammed
What is the direction and net electric force on q_{1}= 5µC located at (0,4)r due to charges q_{2}=7mu located at (0,0)m and q_{3}=3\mu C located at (4,0)m?
Kate Reply
what is the change in momentum of a body?
Eunice Reply
what is a capacitor?
Raymond Reply
Capacitor is a separation of opposite charges using an insulator of very small dimension between them. Capacitor is used for allowing an AC (alternating current) to pass while a DC (direct current) is blocked.
Gautam
A motor travelling at 72km/m on sighting a stop sign applying the breaks such that under constant deaccelerate in the meters of 50 metres what is the magnitude of the accelerate
Maria Reply
please solve
Sharon
8m/s²
Aishat
What is Thermodynamics
Muordit
velocity can be 72 km/h in question. 72 km/h=20 m/s, v^2=2.a.x , 20^2=2.a.50, a=4 m/s^2.
Mehmet
A boat travels due east at a speed of 40meter per seconds across a river flowing due south at 30meter per seconds. what is the resultant speed of the boat
Saheed Reply
50 m/s due south east
Someone
which has a higher temperature, 1cup of boiling water or 1teapot of boiling water which can transfer more heat 1cup of boiling water or 1 teapot of boiling water explain your . answer
Ramon Reply
I believe temperature being an intensive property does not change for any amount of boiling water whereas heat being an extensive property changes with amount/size of the system.
Someone
Scratch that
Someone
temperature for any amount of water to boil at ntp is 100⁰C (it is a state function and and intensive property) and it depends both will give same amount of heat because the surface available for heat transfer is greater in case of the kettle as well as the heat stored in it but if you talk.....
Someone
about the amount of heat stored in the system then in that case since the mass of water in the kettle is greater so more energy is required to raise the temperature b/c more molecules of water are present in the kettle
Someone
definitely of physics
Haryormhidey Reply
how many start and codon
Esrael Reply
what is field
Felix Reply
physics, biology and chemistry this is my Field
ALIYU
field is a region of space under the influence of some physical properties
Collete
what is ogarnic chemistry
WISDOM Reply
determine the slope giving that 3y+ 2x-14=0
WISDOM
Another formula for Acceleration
Belty Reply
a=v/t. a=f/m a
IHUMA
innocent
Adah
pratica A on solution of hydro chloric acid,B is a solution containing 0.5000 mole ofsodium chlorid per dm³,put A in the burret and titrate 20.00 or 25.00cm³ portion of B using melting orange as the indicator. record the deside of your burret tabulate the burret reading and calculate the average volume of acid used?
Nassze Reply
how do lnternal energy measures
Esrael
Two bodies attract each other electrically. Do they both have to be charged? Answer the same question if the bodies repel one another.
JALLAH Reply
No. According to Isac Newtons law. this two bodies maybe you and the wall beside you. Attracting depends on the mass och each body and distance between them.
Dlovan
Are you really asking if two bodies have to be charged to be influenced by Coulombs Law?
Robert
like charges repel while unlike charges atttact
Raymond
What is specific heat capacity
Destiny Reply
Specific heat capacity is a measure of the amount of energy required to raise the temperature of a substance by one degree Celsius (or Kelvin). It is measured in Joules per kilogram per degree Celsius (J/kg°C).
AI-Robot
specific heat capacity is the amount of energy needed to raise the temperature of a substance by one degree Celsius or kelvin
ROKEEB
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Source:  OpenStax, College algebra. OpenStax CNX. Feb 06, 2015 Download for free at https://legacy.cnx.org/content/col11759/1.3
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