The area of the rectangle is (18x-12) square inches. write an expression that represents the length of the rectangle. and find the perimeter of the rectangle.

the width is 6in, by the way.

We let l be the length of the rectangle.

The formula for the area of a rectangle is,
A = l w

Substituting the given:
(18x-12) = l (6)
l = 3x-2 (expression for the length)

The perimeter of a rectangle has the formula:
P = 2 (l + w)

Substituting the given and the expression for the length
P = 2 (3x-2 + 6)
P = 2(3x + 4)
P = 6x +8 (expression for the perimeter of the rectangle)