Question

Divide 9x^2-21x-20 by x-1

Answer 1

`9 x^(3)-30 x^(2) +x+20`

Answer 2

Answer:

1) quotient: 9x - 12
2) remainder: - 32

Step-by-step explanation:

I will use short division, which consists in using just the coefficients.

This is the full operation:

literal x^2 x 0
coefficient | 9 - 21 - 20
|
1 | 9 - 12
-------------------------------------
9 -12 - 32

Result:

1) quotient: 9x - 12
2) remainder: - 32

You can prove the result by multiplyin (9x - 12) times (x - 1) and then adding the remainder (-32).

=> (9x - 12) (x - 1) - 32 = 9x^2 - 9x - 12x + 12 - 32 = 9x^2 - 21x - 20 which proves the answer.