2x + 1 = 9
First step is to remove the integer (whole number)
Remove 1
2x = 8
Then divide by 2 to find x
x = 4
P = 58 inches
58 = 2 x height + 2 x width
58 = 2h + 2w
58 = 2 x 18 + 2w
58 = 36 + 2w
Get rid of the whole numbers
22 = 2w
Divide b 2 to find w
w = 11