A) X^2-2x=-x+2
(=)x²-2x+x-2=0
(=)x(x-2)+(x-2)=0
(=)(x+1)(x-2)=0
(=)\(\left[ \begin{array}{l}x+1=0\\x-2=0\end{array} \right.\) (=)\(\left[ \begin{array}{l}x=-1\\x=2\end{array} \right.\)
S={-1;2}
B) x²+4x-5=0
(=)x²-x+5x-5=0
(=)x(x-1)+5(x-1)=0
(=)(x+5)(x-1)=0
(=)\(\left[ \begin{array}{l}x+5=0\\x-1=0\end{array} \right.\) (=)\(\left[ \begin{array}{l}x=-5\\x=1\end{array} \right.\)
S={-5;1}
C) x²-3x=-2
(=)x²-3x+2=0
(=)x²-x-2x+2=0
(=)x(x-1)-2(x-1)=0
(=)(x-2)(x-1)=0
(=)\(\left[ \begin{array}{l}x-2=0\\x-1=0\end{array} \right.\) (=)\(\left[ \begin{array}{l}x=2\\x=1\end{array} \right.\)
S={1;2}
