Réponse :

Explications étape par étape :

1/a* f(x)=(2x+1)²-(x+2)²

=(2x)²+2×2x×1+1²-(x²+2x×2+2²)

=4x²+4x+1-x²-4x-4

f(x)=3x²-3

b* f(x)=3x²-3

f(x)=3(x²-1)

2/a* f(0)=3(0²-1)

f(0)=3(0-1)

f(0)=3(-1)

f(0)=(-3)

b* f(√2)=3√2²-3

=3×2-3

=6-3

f(√2)=3