`(x+2)^2-9=0`
`⇔(x+2-3)(x+3+2)=0`
`⇔(x-1)(x+5)=0`
`⇔`\(\left[ \begin{array}{l}x-1=0\\x+5=0\end{array} \right.\)
`⇔`\(\left[ \begin{array}{l}x-1=0\\x+5=0\end{array} \right.\)
`⇔`\(\left[ \begin{array}{l}x=1\\x=-5\end{array} \right.\)
`x^2-2x+1=25`
`⇔x^2-2x-24=0`
`⇔(x-6)(x+4)=0`
`⇔`\(\left[ \begin{array}{l}x-6=0\\x+4=0\end{array} \right.\)
`⇔`\(\left[ \begin{array}{l}x-6=0\\x+4=0\end{array} \right.\)
`⇔`\(\left[ \begin{array}{l}x=6\\x=-4\end{array} \right.\)
`4x(x-1)-(2x+5)(2x-5)=1`
`⇔4x^2-4x-(4x^2-25)=1`
`⇔25-1-4x=0`
`⇔24-4x=0`
`⇔4(6-x)=0`
`⇔6-x=0`
`⇔x=6`
`3(x+2)^2+(2x-1)^2-7(x-3)(x+3)=28`
`⇔3(x^2+4x+4)+(4x^2-4x+1)-7(x^2-9)-28=0`
`⇔8x+12+1+63-28=0`
`⇔8x+48=0`
`⇔8(x+6)=0`
`⇔x+6=0`
`⇔x=-6`
