`1)(x-1)(x+1)-(x-2)(x+4)=10`
`⇔x²-1-(x²+4x-2x-8)=10`
`⇔x²-1-x²-4x+2x+8=10`
`⇔-2x+7=10`
`⇔-2x=10-7`
`⇔-2x=3`
`⇔x=-3/2`
Vậy `x=-3/2`
`2)(2x-3)(3x+5)+3=6x(x+2)`
`⇔6x²+10x-9x-15+3=6x²+12x`
`⇔6x²+x-12=6x²+12x`
`⇔6x²+x-6x²-12x=12`
`⇔-11x=12`
`⇔x=-12/11`
Vậy `x=-12/11`
`3)(x²+x+1)(x+1)-2x=x²(x+2)+2(x+3)`
`⇔x³+x²+x²+x+x+1-2x=x³+2x²+2x+6`
`⇔x³+2x²+1=x³+2x²+2x+6`
`⇔x³+2x²-x³-2x²-2x=6-1`
`⇔-2x=5`
`⇔x=-5/2`
Vậy `x=-5/2`
`4)(5x-4)(x+5)-(x-5)(-x²+4)=x³+3`
`⇔5x²+25x-4x-20-(-x³+4x+5x²-20)=x³+3`
`⇔5x²+25x-4x-20+x³-4x-5x²+20=x³+3`
`⇔5x²+25x-4x+x³-4x-5x²-x³=3+20-20`
`⇔17x=3`
`⇔x=3/17`
Vậy `x=3/17`
`5)-(x+3)(x-4)+(x-1)(x+1)=10`
`⇔-(x²-4x+3x-12)+x²+x-x-1=10`
`⇔-x²+4x-3x+12+x²+x-x-1=10`
`⇔-x²+4x-3x+x²+x-x=10-12+1`
`⇔x=-1`
Vậy `x=-1`
`6)(2x-1)(x-2)-(x+3)(2x+7)=3`
`⇔2x²-4x-x+2-(2x²+7x+6x+21)=3`
`⇔2x²-4x-x+2-2x²-7x-6x-21=3`
`⇔2x²-4x-x-2x²-7x-6x=3-2+21`
`⇔-18x=22`
`⇔x=-11/9`
Vậy `x=-11/9`
`7)(x-3)(x+2)-x(x+4)=5x-2`
`⇔x²+2x-3x-6-x²-4x=5x-2`
`⇔x²+2x-3x-x²-4x-5x=-2+6`
`⇔-10x=4`
`⇔x=-2/5`
Vậy `x=-2/5`
`8)(2x+3)(2+2x)-(2x-1)(2x+3)=4`
`⇔4x+4x²+6+6x-(4x²+6x-2x-3)=4`
`⇔4x+4x²+6+6x-4x²-6x+2x+3=4`
`⇔4x+4x²+6x-4x²-6x+2x=4-6-3`
`⇔6x=-5`
`⇔x=-5/6`
Vậy `x=-5/6`
`9)(6x+7)(2x-3)-(3x-5)(4x+1)=8`
`⇔12x²-18x+14x-21-(12x²+3x-20x-5)=8`
`⇔12x²-18x+14x-21-12x²-3x+20x+5=8`
`⇔12x²-18x+14x-12x²-3x+20x=8+21-5`
`⇔13x=24`
`⇔x=24/13`
Vậy `x=24/13`
