[tex]( x –3 )² +( x – 3 )( 1 – 2x )[/tex]
[tex]x {}^ 2−2x×3+3 {}^ 2+(x−3)(1−2x)
[/tex]
[tex]x {}^{2} −2x×3+3 {}^{2} +x−2x {}^{2} −3+6x
[/tex]
[tex]x {}^{2} −2x×3+9+x−2x {}^{2} −3+6x
[/tex]
[tex]x {}^{2} −6x+9+x−2x {}^{2} −3+6x
[/tex]
[tex](x {}^{2} −2x {}^{2} )+(−6x+x+6x)+(9−3)
[/tex]
[tex]−x {}^{2} +x+6
[/tex]
Voila, Bon courage.
