Đáp án:
`=x^{4}−x²+6x−9`
Giải thích các bước giải:
`(x²+x−3)(x²−x+3)`
`=(x²−x+3)⋅x²+x(x²−x+3)−3(x²−x+3)`
`=x^{4}−x⋅x²+3x²+x(x²−x+3)−3(x²−x+3)`
`=x^{4}−x.x²+3x²+x³−x.x+3x−3(x²−x+3)`
`=x^{4}−x.x²+3x²+x³−x²+3x−3(x²−x+3)`
`=x^{4}−x.x²+3x²+x³−x²+3x−3x²+3x-9`
`=x^{4}−x.x²−1x²+x³+3x+3x−9`
`=x^{4}−x.x²−x²+x³+6x−9`
`=x^{4}−x³−x²+x³+6x-9`
`=x^{4}−x²+6x−9`