`A1)`
`x(x+1)-x²+1=0`
`⇔x(x+1)-(x²-1)=0`
`⇔x(x+1)-(x+1)(x-1)=0`
`⇔(x+1)[x-(x-1)]=0`
`⇔(x+1)(x-x+1)=0`
`⇔(x+1).1=0`
`⇔x+1=0`
`⇔x=-1`
Vậy `x=-1`
`A2)`
`4x(x-2)-6+3x=0`
`⇔4x(x-2)+(3x-6)=0`
`⇔4x(x-2)+3(x-2)=0`
`⇔(x-2)(4x+3)=0`
`⇔`$\left[\begin{matrix} x-2=0\\ 4x+3=0\end{matrix}\right.$
`⇔`$\left[\begin{matrix} x=2\\ x=-\dfrac{3}{4}\end{matrix}\right.$
Vậy `x∈{2;-3/4}`
`A3)`
`x(x+2)-3(x+2)=0`
`⇔(x+2)(x-3)=0`
`⇔`$\left[\begin{matrix} x+2=0\\ x-3=0\end{matrix}\right.$
`⇔`$\left[\begin{matrix} x=-2\\ x=3\end{matrix}\right.$
Vậy `x∈{-2;3}`
`B1)`
`(x+3)²-(x+2)(x-2)=4x+17`
`⇔x²+6x+9-(x²-2²)=4x+17`
`⇔x²+6x+9-(x²-4)=4x+17`
`⇔x²+6x+9-x²+4=4x+17`
`⇔(x²-x²)+6x+(9+4)=4x+17`
`⇔6x+13=4x+17`
`⇔6x-4x=17-13`
`⇔2x=4`
`⇔x=4:2`
`⇔x=2`
Vậy `x=2`
`B2)`
`(2x+1)²-(4x-1)(x-3)-15=0`
`⇔4x²+4x+1-(4x²-12x-x+3)-15=0`
`⇔4x²+4x+1-4x²+12x+x-3-15=0`
`⇔(4x²-4x²)+(4x+12x+x)+(1-3-15)=0`
`⇔17x-17=0`
`⇔17x=17`
`⇔x=17:17`
`⇔x=1`
Vậy `x=1`
`B3)`
`(2x+3)(x-1)+(2x-3)(1-x)=0`
`⇔(2x+3)(x-1)-(2x-3)(x-1)=0`
`⇔(x-1)[(2x+3)-(2x-3)]=0`
`⇔(x-1)(2x+3-2x+3)=0`
`⇔(x-1).6=0`
`⇔x-1=0`
`⇔x=1`
Vậy `x=1`
