## Introductory Algebra for College Students (7th Edition)

$8$ inches
The perimeter is the sum of the sides' lengths $P=\displaystyle \frac{4x+9}{x+4}+\frac{7}{x+4}+\frac{4x+9}{x+4}+\frac{7}{x+4}$ To add/subtract rational expressions with the same denominator, add/subtract numerators and place the sum/difference over the common denominator. $P=\displaystyle \frac{4x+9+7+4x+9+7}{x+4}$ $=\displaystyle \frac{8x+32}{x+4}$ $=\displaystyle \frac{8(x+4)}{(x+4)}$ ... common factors cancel, =$8$ inches