What must be subtracted from 4x4 2x3 6x² x 5 so that the result is exactly divisible by 2x² 3x 2?

What must be subtracted from x4+2 x3 2 x2+4 x+6 so that the result is exactly divisible by x2+2 x 3 ?

what must be subtracted from 4x4 - 2x3 - 6x2 + x - 5 so that the resulting polynomial is exactly divisible by 2x2 + x - 1