Area of a rectangle = length x height
Area = 135
Height = X
Lenght = x +6
135 = x * x+6
Simplify:
135 = x^2 +6x
Subtract 135 from both sides:
x^2 + 6x - 135 = 0
Solve:
2 numbers when added need to equal 6 and when multiplied equal -135
x = 9 and x = -15
The height can't be a negative number so the height is 9
Length = 9 +6 = 15
Height = 9cm, Length = 15 cm
