Use the binomial theorem to find the coefficient of x^ay^b in the expansion of (5x^2 + 2y^3)^6, where a) a = 6, b = 9. b) a = 2, b = 15.c) a = 3, b = 12. d) a = 12, b = 0.e) a = 8, b = 9.

Sanderson is having trouble with his assignment. his shown work is as follows: − 3 7 7 3 = − 3 7 × 7 3 = − 21 21 = −1 however, his answer does not match the answer that his teacher gives him. complete the description of sanderson's mistake. find the correct answer.