Réponse :
1) f(1) = 1*2 + 4*1 +2 = 2+4+2 = 8
2) f(-3) = -3*2 + 4*-3 +2 = -6 - 14 + 2 = -18
3) j'ai pas de calculatrice
4) f (x) = x2 + 4x + 2 = 2
x2 + 4x + 2 = 2
x2 + 4x + 2 - 2 = 0
2x + 4x = 0
6x(/6) = 0(/6)
x = 0
Verification du 4)
f (x) = x2 + 4x + 2
f (0) = 0*2 + 4*0 + 2
f (0) = 0 + 0 + 2 = 2