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A game room has a perimeter of 70 ft. The length is five more than twice the width. How many ft 2 of new carpeting should be ordered?

250 ft 2

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Solving a volume problem

Find the dimensions of a shipping box given that the length is twice the width, the height is 8 inches, and the volume is 1,600 in. 3 .

The formula for the volume of a box is given as V = L W H , the product of length, width, and height. We are given that L = 2 W , and H = 8. The volume is 1,600 cubic inches.

V = L W H 1 , 600 = ( 2 W ) W ( 8 ) 1 , 600 = 16 W 2 100 = W 2 10 = W

The dimensions are L = 20 in., W = 10 in., and H = 8 in.

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Key concepts

  • A linear equation can be used to solve for an unknown in a number problem. See [link] .
  • Applications can be written as mathematical problems by identifying known quantities and assigning a variable to unknown quantities. See [link] .
  • There are many known formulas that can be used to solve applications. Distance problems, for example, are solved using the d = r t formula. See [link] .
  • Many geometry problems are solved using the perimeter formula P = 2 L + 2 W , the area formula A = L W , or the volume formula V = L W H . See [link] , [link] , and [link] .

Section exercises

Verbal

To set up a model linear equation to fit real-world applications, what should always be the first step?

Answers may vary. Possible answers: We should define in words what our variable is representing. We should declare the variable. A heading.

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Use your own words to describe this equation where n is a number:

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5 ( n + 3 ) = 2 n

If the total amount of money you had to invest was $2,000 and you deposit x amount in one investment, how can you represent the remaining amount?

2 , 000 x

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If a man sawed a 10-ft board into two sections and one section was n ft long, how long would the other section be in terms of n ?

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If Bill was traveling v mi/h, how would you represent Daemon’s speed if he was traveling 10 mi/h faster?

v + 10

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Real-world applications

For the following exercises, use the information to find a linear algebraic equation model to use to answer the question being asked.

Mark and Don are planning to sell each of their marble collections at a garage sale. If Don has 1 more than 3 times the number of marbles Mark has, how many does each boy have to sell if the total number of marbles is 113?

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Beth and Ann are joking that their combined ages equal Sam’s age. If Beth is twice Ann’s age and Sam is 69 yr old, what are Beth and Ann’s ages?

Ann: 23 ; Beth: 46

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Ben originally filled out 8 more applications than Henry. Then each boy filled out 3 additional applications, bringing the total to 28. How many applications did each boy originally fill out?

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For the following exercises, use this scenario: Two different telephone carriers offer the following plans that a person is considering. Company A has a monthly fee of $20 and charges of $.05/min for calls. Company B has a monthly fee of $5 and charges $.10/min for calls.

Questions & Answers

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Ewa Reply
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Moses
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Fredrick Reply
the transfer of energy by a force that causes an object to be displaced; the product of the component of the force in the direction of the displacement and the magnitude of the displacement
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difference between model and theory
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Is the ship moving at a constant velocity?
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The full note of modern physics
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introduction to applications of nuclear physics
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yes
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aluet
Show that the equal masses particles emarge from collision at right angle by making explicit used of fact that momentum is a vector quantity
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yh
Isaac
A wave is described by the function D(x,t)=(1.6cm) sin[(1.2cm^-1(x+6.8cm/st] what are:a.Amplitude b. wavelength c. wave number d. frequency e. period f. velocity of speed.
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A body is projected upward at an angle 45° 18minutes with the horizontal with an initial speed of 40km per second. In hoe many seconds will the body reach the ground then how far from the point of projection will it strike. At what angle will the horizontal will strike
Gufraan Reply
Suppose hydrogen and oxygen are diffusing through air. A small amount of each is released simultaneously. How much time passes before the hydrogen is 1.00 s ahead of the oxygen? Such differences in arrival times are used as an analytical tool in gas chromatography.
Ezekiel Reply
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Samuel
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the science concerned with describing the interactions of energy, matter, space, and time; it is especially interested in what fundamental mechanisms underlie every phenomenon
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nuclei having the same Z and different N s
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Practice Key Terms 3

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Source:  OpenStax, Algebra and trigonometry. OpenStax CNX. Nov 14, 2016 Download for free at https://legacy.cnx.org/content/col11758/1.6
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