bonsoir
a = ( 2 x - 7)² - 49 = identité remarquable vu en 3 ème ..
a = ( 2 x - 7 - 7) ( 2 x - 7 + 7) = ( 2 x - 14 ) ( 2 x )
b = ( 3 x - 3) ( 2 x + 7 - 3 x + 3 )
= ( 3 x - 3) ( - x + 10)
continue
4 x + 7 = - 6 x - 4 - 2x
4 x + 6 x + 2 x = - 4 - 7
12 x = - 11
x = - 11/12
10 x - 10 - 6 x = 6 - 5 x
10 x - 6 x + 5 x = 6 + 10
9 x = 16
x = 16/9
continue, je t'ai rafraîchi la mémoire