Try to expand and you will get a linear equation. After that you can solve it by moving terms around and simplifying it.
(x + A)(x + B) = (x + C)(x + D)
x2 + (A + B)x + AB = x2 + (C + D)x + CD
(A + B)x + AB = (C + D)x + CD
(A + B)x - (C + D)x = CD - AB
(A + B - C - D)x = CD - AB
x = ____________________
One step left for you to complete.