Solve each of the following quadratic equations:
taking LCM
4x2 + 4ax + 2bx = - 2ab cross multiplying
4x2 + 4ax + 2bx + 2ab = 0
4x(x + a) + 2b(x + a) = 0 taking 4x common from first two terms and 2b from last two
(x + a) (4x + 2b) = 0
(x + a) = 0 or (4x + 2b) = 0
Hence the roots of equation are 
56