+36916 Set the two givens =
(x-2a)(x-b) = x^2 +ax+b
x^2 -2ax-bx+2ab = x^2+ax+b
-2ax-bx+2ab = ax+b
so -2ax-bx = ax and 2ab = b
-2a-b = a and 2 ab = b
-b = 3a and 2a = 1
-b = 3a and a = 1/2
-b = 3/2
b = -3/2 You can add them together...I hope ! 
