Area = L * W
Area = (x + 2)(2x - 5) = 56
x^2 +4x - 5x - 10 = 56
x^2 - x - 10 = 56
x^2 - x - 66 This does not factor nicely
You have to use the quadratic formula.
a = 1
b = - 1
c = - 66
x = (-b) +/- sqrt(b^2 - 4ac)
================
2a
x = 1 + /- sqrt(1^2 - 4(1)(-66)
===================
2(1)
= 1 +/- sqrt (265)
==============
2
= 17.279/2
= 8.639 which rounds to 9
