Question

the length of a rectangle is 3n + 2 and its width is n - 1. find the perimeter of the rectangle when n = 4 inches. (the formula for perimeter of a rectangle is twice the sum of its length and its width.)

Explanation:

Step1: Find the length when n = 4

Substitute n = 4 into the length formula $l=3n + 2$.
$l=3\times4+2=12 + 2=14$ inches.

Step2: Find the width when n = 4

Substitute n = 4 into the width formula $w=n - 1$.
$w=4-1=3$ inches.

Step3: Calculate the perimeter

Use the perimeter formula $P = 2(l + w)$.
$P=2\times(14 + 3)=2\times17 = 34$ inches.

Answer:

34 inches