Question

Find the illegal values of c in the multiplication statement c^2-3c-10/c^2+5c-14-c^2-c-2/c^2-2c-15

Answer 1

c^2 + 5c - 14 = 0
(c-2)(c+7) = 0
c-2 = 0 or c+7 = 0
c = 2 or c = -7

c^2 - 2c - 15 = 0
(c-5)(c+3) = 0
c-5 = 0 or c+3 = 0
c = 5 or c = -3