In the calculation result of (AX2 + BX + 1) (2x2-3x-1), there is no X3 term and X term

In the calculation result of (AX2 + BX + 1) (2x2-3x-1), there is no X3 term and X term


(AX2 + BX + 1) (2x2-3x-1) = 2ax4-3ax3-ax2 + 2bx3-3bx2-bx + 2x2-3x-1 = 2ax4 + (2b-3a) X3 + (- a-3b + 2) x2 + (- 3-B) X-1, ∵ in the calculation result of (AX2 + BX + 1) (2x2-3x-1), there is no X3 term and X term, ∵ 2b-3a = 0, - 3-B = 0, the solution is a = - 2, B = - 3