Hướng dẫn trả lời:
b) `(x^4 + x^3 - 6x^2 - 5x + 5) ÷ (x^2 + x - 1)`
`= (x^4 + x^3 - x^2 - 5x^2 - 5x + 5) ÷ (x^2 + x - 1)`
`= [(x^4 + x^3 - x^2) - (5x^2 + 5x - 5)] ÷ (x^2 + x - 1)`
`= [x^2*(x^2 + x - 1) - 5*(x^2 + x - 1)] ÷ (x^2 + x - 1)`
`= (x^2 - 5)*(x^2 + x - 1) ÷ (x^2 + x - 1)`
`= x^2 - 5`
Đáp án:
`(x^4 + x^3 - 6x^2 - 5x + 5) ÷ (x^2 + x - 1) = x^2 - 5`
