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)