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This module is from Elementary Algebra by Denny Burzynski and Wade Ellis, Jr. Operations with algebraic expressions and numerical evaluations are introduced in this chapter. Coefficients are described rather than merely defined. Special binomial products have both literal and symbolic explanations and since they occur so frequently in mathematics, we have been careful to help the student remember them. In each example problem, the student is "talked" through the symbolic form.Objectives of this module: be able to multiply a polynomial by a monomial, be able to simplify +(a + b) and -(a - b), be able to multiply a polynomial by a polynomial.

Overview

  • Multiplying a Polynomial by a Monomial
  • Simplifying + ( a + b ) and ( a + b )
  • Multiplying a Polynomial by a Polynomial

Multiplying a polynomial by a monomial

Multiplying a polynomial by a monomial is a direct application of the distributive property.

Distributive property

The product of a monomial a and a binomial b plus c is equal to ab plus ac. This is the distributive property. In the expression, there are two arrows originating from the monomial, a, and pointing towards the terms b and c of the binomial.

The distributive property suggests the following rule.

Multiplying a polynomial by a monomial

To multiply a polynomial by a monomial, multiply every term of the polynomial by the monomial and then add the resulting products together.

Sample set a

10 a b 2 c ( 125 a 2 ) = 1250 a 3 b 2 c

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Practice set a

Determine the following products.

( a 2 2 b + 6 ) 2 a

2 a 3 4 a b + 12 a

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8 a 2 b 3 ( 2 a + 7 b + 3 )

16 a 3 b 3 + 56 a 2 b 4 + 24 a 2 b 3

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4 x ( 2 x 5 + 6 x 4 8 x 3 x 2 + 9 x 11 )

8 x 6 + 24 x 5 32 x 4 4 x 3 + 36 x 2 44 x

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( 3 a 2 b ) ( 2 a b 2 + 4 b 3 )

6 a 3 b 3 + 12 a 2 b 4

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5 m n ( m 2 n 2 + m + n 0 ) , n 0

5 m 3 n 3 + 5 m 2 n + 5 m n

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Use a calculator. 6.03 ( 2.11 a 3 + 8.00 a 2 b )

12.7233 a 3 + 48.24 a 2 b

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Simplifying + ( a + b ) And - ( a + b )

+ ( a + b ) And - ( a + b )

Oftentimes, we will encounter multiplications of the form

+ 1 ( a + b ) or - 1 ( a + b )

These terms will actually appear as

+ ( a + b ) and - ( a + b )

Using the distributive property, we can remove the parentheses.

Removal of a set of parentheses preceded by a plus sign using the distributive property. See the longdesc for a full description.

The parentheses have been removed and the sign of each term has remained the same.

Removal of a set of parentheses preceded by a minus sign using the distributive property. See the longdesc for a full description.

The parentheses have been removed and the sign of each term has been changed to its opposite.

  1. To remove a set of parentheses preceded by a " + " sign, simply remove the parentheses and leave the sign of each term the same.
  2. To remove a set of parentheses preceded by a “ ” sign, remove the parentheses and change the sign of each term to its opposite sign.

Sample set b

Simplify the expressions.

( 6 x 1 ) .

This set of parentheses is preceded by a “ + ’’ sign (implied). We simply drop the parentheses.

( 6 x 1 ) = 6 x 1

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( 14 a 2 b 3 6 a 3 b 2 + a b 4 ) = 14 a 2 b 3 6 a 3 b 2 + a b 4

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( 21 a 2 + 7 a 18 ) .

This set of parentheses is preceded by a “ ” sign. We can drop the parentheses as long as we change the sign of every term inside the parentheses to its opposite sign.

( 21 a 2 + 7 a 18 ) = 21 a 2 7 a + 18

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( 7 y 3 2 y 2 + 9 y + 1 ) = 7 y 3 + 2 y 2 9 y 1

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Practice set b

Simplify by removing the parentheses.

( a 2 6 a + 10 )

a 2 6 a + 10

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( x + 2 y )

x 2 y

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( 5 m 2 n )

5 m + 2 n

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( 3 s 2 7 s + 9 )

3 s 2 + 7 s 9

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Multiplying a polynomial by a polynomial

Since we can consider an expression enclosed within parentheses as a single quantity, we have, by the distributive property,

Finding the product of the binomials 'a plus b' and 'c plus d', using the distributive property. See the longdesc for a full description.

For convenience we will use the commutative property of addition to write this expression so that the first two terms contain a and the second two contain b .

Questions & Answers

Ayele, K., 2003. Introductory Economics, 3rd ed., Addis Ababa.
Widad Reply
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Ariel
?
Ariel
What is economics
Widad Reply
the study of how humans make choices under conditions of scarcity
AI-Robot
U(x,y) = (x×y)1/2 find mu of x for y
Desalegn Reply
U(x,y) = (x×y)1/2 find mu of x for y
Desalegn
what is ecnomics
Jan Reply
this is the study of how the society manages it's scarce resources
Belonwu
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macroeconomic is the branch of economics which studies actions, scale, activities and behaviour of the aggregate economy as a whole.
husaini
etc
husaini
difference between firm and industry
husaini Reply
what's the difference between a firm and an industry
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firm is the unit which transform inputs to output where as industry contain combination of firms with similar production 😅😅
Abdulraufu
Suppose the demand function that a firm faces shifted from Qd  120 3P to Qd  90  3P and the supply function has shifted from QS  20  2P to QS 10  2P . a) Find the effect of this change on price and quantity. b) Which of the changes in demand and supply is higher?
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Jan
economics is a science that studies human behaviour as a relationship b/w ends and scares means which have alternative uses
Jan
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out-of-pocket costs for a firm, for example, payments for wages and salaries, rent, or materials
AI-Robot
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identify a demand and a supply curve
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Demand curve shows that how supply and others conditions affect on demand of a particular thing and what percent demand increase whith increase of supply of goods
Israr
Hi Sir please how do u calculate Cross elastic demand and income elastic demand?
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Source:  OpenStax, Elementary algebra. OpenStax CNX. May 08, 2009 Download for free at http://cnx.org/content/col10614/1.3
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