OK c'est parti !
[tex](2x+1)^2 = (2x+1)(x-3) \\ \textless \ =\ \textgreater \ (2x+1)^2 - (2x+1)(x-3)=0[/tex]
[tex]\ \textless \ =\ \textgreater \ (2x+1) [(2x+1)-(x-3) = 0
\\ \ \textless \ =\ \textgreater \ (2x+1) (2x-x+1+3) = 0
[/tex]
[tex]\ \textless \ =\ \textgreater \ (2x+1) (x+4) = 0
[/tex]
Si a fois b = 0 alors a=0 ou b=0
[tex]\ \textless \ =\ \textgreater \ (2x+1) = 0 ou (x+4) = 0
\\ \ \textless \ =\ \textgreater \ x=- \frac{1}{2} ou x=-4
x={-4;-1/2}
Si tu as des questions n'hésite pas !
