Đáp án:
Giải thích các bước giải:
`a, `
`x(2x^2-3)-x^2(5x+1)+x^2`
`=x^3-3x-5x^3-x^2+x^2`
`=(x^3-5x^3)-3x+(-x^2+x^2)`
`=-4x^3-3x`
`b,`
`3x(x-2)-5x(1-x)-8(x^2-3)`
`=3x^2-6x-5x+5x^2-8x^2+24`
`=(3x^2+5x^2-8x^2)+(-6x-5x)+24`
`=-11x+24`
`c,`
`1/2.x^2.(6x-3)-x.(x^2+1/2)+1/2`
`=3x^3-3/2.x^2-x^3-1/2.x+1/2`
`=(3x^3-x^3)-3/2.x^2-1/2.x+1/2`
`=2x^3-3/2.x^2-1/2.x+1/2`
$#NOCOPY$