Question

The area of a rectangle is 56 cm. The length is 2cm more than x and the width is 5 cm less than twice x.Solve for x

Answer 1

Area of a rectangle is A = L*W.

Here, A = 56 cm^2 (not 56 cm).

= (56 cm^2)=( L )( W ) = (x+2)*(2x-5) = 2x^2 - 5x + 4x - 10

Simplifying, 2x^2 - 5x + 4x - 10 = 56, or 2x^2 - x - 66 = 0.

Solve this using the quadratic formula:

-(-1) plus or minus sqrt ( (-1)^2 - 4(2)(-66) )
x = -------------------------------------------------------------
2(2)

Finish the work: find x. Most likely you will need to check both of the roots. Keep in mind that x will likely be a positive number.