Bonsoir,
[tex]a)\ (3x-2)(4x+7)=-14\\12x^2+21x-8x-14=-14\\12x^2+21x-8x=-14+14\\12x^2+13x=0\\x(12x+13)=0\\x=0\ \ ou\ \ 12x+13=0\\x=0\ \ ou\ \ 12x=-13\\\\\boxed{x=0\ \ ou\ \ x=-\dfrac{13}{12}}[/tex]
[tex]b)\ (3x-2)(4x+7)=0\\3x-2=0\ \ ou\ \ 4x+7=0\\3x=2\ \ ou\ \ 4x=-7\\\\\boxed{x=\dfrac{2}{3}\ \ ou\ \ x=-\dfrac{7}{4}}[/tex]
[tex]c)\ (3x-2)-(4x+7)=0\\3x-2-4x-7=0\\-x-9=0\\-x=9\\\\\boxed{x=-9}[/tex]
[tex]d)\ (7x-12)(2x+2)-(4x+6)(7x-12)=0\\(7x-12)[(2x+2)-(4x+6)]=0\\(7x-12)(2x+2-4x-6)=0\\(7x-12)(-2x-4)=0\\7x-12=0\ \ ou\ \ -2x-4=0\\7x=12\ \ ou\ \ -2x=4\\\\x=\dfrac{12}{7}\ \ ou\ \ x=\dfrac{4}{-2}\\\\\boxed{x=\dfrac{12}{7}\ \ ou\ \ x=-2}[/tex]
