Question

Find a polynomial, which if substituted for M will make the equation an identity:

M+M=8x^2−4x−6

Answer 1

That would be M = 4x^2 - 2x - 3 because

4x^2 - 2x - 3 + 4x^2 - 2x - 3 = 8x^2 - 4x - 6