Question 150525
Given: Length = Width + 3
Width = Length - 3
Area = Length*Width
Area = 108

{{{A = L*W}}}
{{{180 = L * (L-3)}}}
{{{180 = L^2 - 3L}}}
{{{0 = L^2 - 3L - 180}}}
{{{0 = (L -15)(L + 12) }}}
Either or both terms must be 0 for the product to equal 0.
Either (L-15) = 0 or (L+12)=0
So L = 15 or L = -12.
Since a length cannot be negative, the length must be 15.