If `A = x^(3), B = 4x^(2) + x -1`, then find AB

If A = x^(3), B = 4x^(2) + x -1, C = x +1 , then find (A -B) (A-C)

If A=2x^(3)-3x^(2)-4x+5, B=2x^(2)-x^(3)+1 and C=x^(2)+x+2 , then find the degree of A+2B-C.

If f(x) = 6x^(4) + 8x^(3) + 17x^(2) + 21x + 7 is divided by g(x) = 3x^(2) + 4x +1 , the remainder is ax + b . Find a and b.