Giải thích các bước giải:
a) `x ^ 2 . (x-1) -4x ^ 2+ 8x -4 =0`
`=>x ^2 .(x-1) -(4x ^ 2- 8x +4) =0`
`=>x ^2 .(x-1) -4(x ^ 2- 2x +1) =0`
`=>x^2 .(x-1)-4(x-1)^2=0`
`=>(x-1)(x^2-4x+4)=0`
`=>(x-1)(x-2)^2=0
`=>`\(\left[ \begin{array}{l}x=1\\x=2\end{array} \right.\)
b) `x^2+3x-18=0`
`=>(x^2-3x)+(6x-18)=0`
`=>x(x-3)+6(x-3)=0`
`=>(x-3)(x+6)=0`
`=>`\(\left[ \begin{array}{l}x=3\\x=-6\end{array} \right.\)