Đáp án + Giải thích các bước giải:
`c)`
`(x-2)xx(x^2-5x+1)-x(x^2+11)`
`=x xx(x^2-5x+1)-2 xx(x^2-5x+1)-x^3-11x`
`=x^3-5x^2+x-2x^2+10x-2-x^3-11x`
`=(x^3-x^3) -(5x^2+2x^2)+(x+10x-11x)-2`
`=-7x^2-2`
`d)`
`x(1-3x)(4-3x)-(x-4)(3x+5)`
`=x(4-3x-12x+9x^2)-(3x^2+5x-12x-20)`
`=x(9x^2-15x+4)-(3x^2-7x-20)`
`=9x^3-15x^2+4x-3x^2+7x+20`
`=9x^3-(15x^2+3x^2)+(4x+7x)+20`
`=9x^3-18x^2+11x+20`