Intermediate Algebra for College Students (7th Edition)

Published by Pearson
ISBN 10: 0-13417-894-7
ISBN 13: 978-0-13417-894-3

Chapter 3 - Review Exercises - Page 249: 18

Answer

Length $=12$ feet. Width $=5$ feet.

Work Step by Step

Step 1:- Assume unknown quantities as variables. Let the length of the rectangle be $=x$. Let the width of the rectangle be $=y$. Step 2:- Write the system of equations. Perimeter of the rectangular tabletop $=34$ feet. $4$ times the length minus $3$ times the width is equal to $33$ feet. The formula for the perimeter of the rectangle is $=2(length+width)$. Or we can write. $\Rightarrow 2(x+y)=34$ ...... (1) $\Rightarrow 4x-3y=33$...... (2) Step 3:- Solve the system of equations. Divide the equation (1) by $2$ and multiply by $3$. $\Rightarrow 3x+3y=51$ ...... (3) Add equation (2) and (3). $\Rightarrow 4x-3y+3x+3y=33+51$ Simplify. $\Rightarrow 7x=84$ Divide both sides by $7$. $\Rightarrow \frac{7x}{7}=\frac{84}{7}$ Simplify. $\Rightarrow x=12$ Plug the value of $x$ into equation (3). $\Rightarrow 3(12)+3y=51$ Isolate $y$. $\Rightarrow y=\frac{51-36}{3}$ Simplify. $\Rightarrow y=5$. Step 4:- Check the answers. Substitute the values of $x$ and $y$ into equation (1). $\Rightarrow 2(12+5)=34$ $\Rightarrow 2(17)=34$ $\Rightarrow 34=34$ True.
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