7ab - 7b + 5ab + a^2 - 2b = a^2 + 12ab - 2ab
3c^3-d^2-5cd+4cd-c^3-7d^2 = 2c^3-8d^2-cd
7x(-42x^3+28x-12x^2+8) = -294x^4 + 196x^2 - 84x^3 + 56x
7ab - 7b + 5ab + a^2 - 2b = a^2 + 12ab - 2ab
3c^3-d^2-5cd+4cd-c^3-7d^2 = 2c^3-8d^2-cd
7x(-42x^3+28x-12x^2+8) = -294x^4 + 196x^2 - 84x^3 + 56x