`(x-2)(x-3)=x^2-2x+1`
`<=> x^2-2x-3x+6-x^2+2x-1=0`
`<=> 5-3x=0`
`<=> 3x=5`
`<=> x=5/3`
`x^3+2x^2-9x-18=0`
`<=> x^2(x+2)-9(x+2)=0`
`<=> (x+2)(x^2-9)=0`
`<=> (x+2)(x-3)(x+3)=0`
`<=>`\(\left[ \begin{array}{l}x+2=0\\x-3=0\\x+3=0\end{array} \right.\)
`<=>`\(\left[ \begin{array}{l}x=-2\\x=3\\x=-3\end{array} \right.\)
`4x^2-12x+9=(5-x)^2`
`<=> 4x^2-12x+9=25-10x+x^2`
`<=> 4x^2-12x+9-x^2+10x-25=0`
`<=> 3x^2-2x-16=0`
`<=> 3x^2-8x+6x-16=0`
`<=> x(3x-8)+2(3x-8)=0`
`<=> (3x-8)(x+2)=0`
`<=>`\(\left[ \begin{array}{l}x+2=0\\3x-8=0\end{array} \right.\)
`<=>`\(\left[ \begin{array}{l}x=-2\\x=\frac{8}{3}\end{array} \right.\)
