Lời giải.
`(-2x^2+5)(x-6)-4x(x^2-7x+2)-2x(x+3)(x-2)-(x^3-x^2)`
`=(-2x^3+12x^2+5x-30)-(4x^3-28x^2+8x)-2x(x^2+3x-2x-6)-(x^3-x^2)`
`=(-2x^3+12x^2+5x-30)-(4x^3-28x^2+8x)-(2x^3+6x^2-4x^2-12x)-(x^3-x^2)`
`=-2x^3+12x^2+5x-30-4x^3+28x^2-8x-2x^3-6x^2+4x^2+12x-x^3+x^2`
`=(-2x^3-4x^3-2x^3-x^3)+(12x^2+28x^2-6x^2+4x^2+x^2)+(5x-8x+12x)-30`
`=-9x^3+39x^2+9x-30.`