☺ Salut ☻
[tex]\rule{6cm}{1mm}[/tex]
[tex]\green{\underline{Formules} \: :}[/tex]
[tex]\green{k(a+b)=ka+kb}[/tex]
[tex]\green{(a+b)(c+d)=ac+ad+bc+bd}[/tex]
[tex]\green{(a+b)^{2}=a^{2}+2ab+b^{2}}[/tex]
[tex]\green{(a-b)^{2}=a^{2}-2ab+b^{2}}[/tex]
[tex]\green{(a+b)(a-b)=a^{2}-b^{2}}[/tex]
[tex]\rule{6cm}{1mm}[/tex]
[tex]\boxed{A(x)=(x-7)^{2}}[/tex]
[tex]\boxed{A(x)=x^{2}-2\times x\times 7 +7^{2}}[/tex]
[tex]\boxed{\boxed{\blue{A(x)=x^{2}-14x+49}}}[/tex]
[tex]\rule{6cm}{1mm}[/tex]
[tex]\boxed{B(x)=(3x+4)^{2}}[/tex]
[tex]\boxed{B(x)=(3x)^{2}+2\times 3x\times 4 +4^{2}}[/tex]
[tex]\boxed{\boxed{\blue{B(x)=9x^{2}+24x+16}}}[/tex]
[tex]\rule{6cm}{1mm}[/tex]
[tex]\boxed{C(x)=(2x-1)(2x+1)}[/tex]
[tex]\boxed{C(x)=(2x)^{2}-1^{2}}[/tex]
[tex]\boxed{\boxed{\blue{C(x)=4x^{2}-1}}}[/tex]
[tex]\rule{6cm}{1mm}[/tex]
[tex]\boxed{D(x)=(3x-7)(-2x+5)}[/tex]
[tex]\boxed{D(x)=3x\times (-2x) +3x\times 5 -7\times (-2x) -7\times 5}[/tex]
[tex]\boxed{D(x)=-6x^{2}+15x+14x-35}[/tex]
[tex]\boxed{\boxed{\blue{D(x)=6x^{2}+29x-35}}}[/tex]
[tex]\rule{6cm}{1mm}[/tex]
