Đáp án:
1/
`-3x(x+2)^2+(x+3).(x-1).(x+1)-(2x-3)^2`
`=-3x(x^2+4x+4)+(x+3).(x^2-1)-(4x^2-12x+9)`
`=-3x^3-12x^2-12x+x^3-x+3x^2-3-4x^2+12x-9`
`=-2x^3-13x^2-x-12`
2/
`(x-3).(x+3).(x+2)-(x-1).(x^2-3)-5x(x+4)^2-(x-5)^2`
`=(x^2-9).(x+2)-(x^3-3x-x^2+3)-5x(x^2+8x+16)-(x^2-10x+25)`
`=x^3+2x^2-9x-18-x^3+3x+x^2-3-5x^3-40x^2-80x-x^2+10x-25`
`=-5x^3-38x^2-76x-46`
3/
`2x(x-4)^2-(x+5).(x-2).(x+2)+2(x+5)^2-(x-1)^2`
`=2x(x^2-8x+16)-(x+5).(x^2-4)+2(x^2+10x+25)-(x^2-2x+1)`
`=2x^3-16x^2+32x-x^3+4x-5x^2+20+2x^2+20x+50-x^2+2x-1`
`=x^3-20x^2+58x+69`
4/
`(x+5)^2-4x(2x+3)^2-(2x-1).(x+3).(x-3)`
`=x^2+10x+25-4x(4x^2+12x+9)-(2x-1).(x^2-9)`
`=x^2+10x+25-16x^3-48x^2-36x-2x^3+18x+x^2-9`
`=-18x^3-46x^2-8x+16`
5/
`-2x(3x+2).(3x-2)+5(x+2)^2-(x-1).(2x+1).(2x+1)`
`=-2x(9x^2-4)+5(x^2+4x+4)-(x-1).(4x^2+4x+1)`
`=-18x^3+8x+5x^2+20x+20-4x^3-4x^2-x+4x^2+4x+1`
`=-22x^3+5x^2+31x+21`
6/
`(7x-8).(7x+8)-10(2x+3)^2+5x(3x-2)^2-4x(x-5)^2`
`=49x^2-64-10(4x^2+12x+9)+5x(9x^2-12x+4)-4x(x^2-10x+25)`
`=49x^2-64-40x^2-120x-90+45x^3-60x^2+20x-4x^3+40x^2-100x`
`=41x^3-11x^2-200x-154`
7/
`(x^2-3).(x^2+3)-5x^2(x+1)^2-(x^2-3x).(x^2-2x)+4x(x+2)^2`
`=x^4-9-5x^2(x^2+2x+1)-(x^4-2x^3-3x^3+6x^2)+4x(x^2+4x+4)`
`=x^4-9-5x^4-10x^3-5x^2-x^4+5x^3-6x^2+4x^3+16x^2+16x`
`=-5x^4-x^3+5x^2+16x-9`
8/
`-6x^2(x+5)^2-(x-3)^2+(x^2-2).(2x^2+1)-4x^2 (3x-4)^2`
`=-6x^2(x^2+10x+25)-(x^2-6x+9)+(2x^4+x^2-4x^2-2)-4x^2(9x^2-24x+16)`
`=-6x^4-60x^3-150x^2-x^2+6x-9+2x^4-3x^2-2-36x^4 +96x^3-64x^2`
`=-40x^4+36x^3-218x^2+6x-11`
9/
`(5x-3y)^2-(4x+y)(4x-y)-(3x+5y)^2+(x-3y).(x+y)`
`=25x^2-30xy+9y^2-16x^2+y^2-(9x^2+30xy+25y^2)+x^2+xy-3xy-3y^2`
`=25x^2-30xy+9y^2-16x^2+y^2-9x^2-30xy-25y^2+x^2+xy-3xy-3y^2`
`=x^2-62xy-18y^2`
10/
`(-4x+2y)(-4x-2y)+(x-5y)^2-(3x+2y)^2-7x(x-3y)`
`=-(4x-2y).-(4x+2y)+(x-5y)^2-(3x+2y)^2-7x(x-3y)`
`=(4x-2y).(4x+2y)+(x-5y)^2-(9x^2+12xy+4y^2)-7x(x-3y)`
`=16x^2-4y^2+x^2-10xy+25y^2-9x^2-12xy-4y^2-7x^2+21xy`
`=x^2+17y^2-xy`
