A rectangle has side lengths (2x - 5) meters and (2x + 6) meters. Write the linear expression in simplest form to represent the perimeter. Find the perimeter if the value of x is 12 meters.
Perimeter:
P = 2 ( L + W )
where
L = length
W = width
In this case x = 12 m
so
L = 2 x + 6 = 2 ∙ 12 + 6 = 24 + 6 = 30 m
W = 2 x - 5 = 2 ∙ 12 - 5 = 24 - 5 = 19 m
P = 2 ( L + W ) = P = 2 ( 30 + 19 ) = 2 ∙ 49
P = 98 m
Linear expression: 4x + 7
Perimeter: 4x + 7 = 4(12) + 7 = 55 meters