Réponse:
1/ a/
(-3x+1)(x-3)=-3x²+9x+x-3
=-3x²+10x-3
=f(x)
b/
f(x)=0
cad (-3x+1)(x-3)=0
cad -3x+1=0 ou x-3=0
cad x=1/3 ou x=3
S={1/3;3}
2/
g(x)=4x²-4x+1-(2x-1)(x+2)
=4x²-4x+1-2x²-4x+x+2
=2x²-7x+3
3/ 4x²-4x+1= (2x)²-2×2x×1+1²
=(2x-1)²
4/
g(x)=4x²-4x+1-(2x-1)(x+2)
=(2x-1)²-(2x-1)(x+2)
=(2x-1)(2x-1-x-2)
=(2x-1)(x-3)
5/
g(x)=0
cad (2x-1)(x-3)=0
cad 2x-1=0 ou x-3=0
cad x=1/2 ou x=3
S={1/2 ;3}
