bonjour,
1a) je te laisse developper et réduire
b) (5x-3)(5x-3-2x+2)=
(5x-3)(3x-1)
2) résoudre E(x)>0 tableau ⇒]-∞;1/3[∪]3/5;+∞[
résoudre E(x) = 3
15x²-14x+3 =3
15x²-14x+3-3 =0
15x²-14x = 0
x(15x-14) = 0
15x-14 =0
x = 14/15
x = 0
E(x)= (5x-3)²
(5x-3)²-2(x-1)(5x-3) = (5x-3)²
(5x-3)-2(x-1)(5x-3)-(5x-3)² = 0
-2(x-1)(5x-3) = 0
x-1 =0
x =1
5x-3 = 0
x = 3/5
