Question

If the polynomial 6x4+8x3+17x2+21x+7 is divided by another polynomial 3x2+4x+1, the remainder comes out to be (ax+b),find a and b

Answer 1

If you divide those two polynomials you get 

2x^2 + 5 + (x - 2)/(3x^2 + 4x + 1)

so your "remainder" will be the "x - 2" 
a = 1
b = 2