Réponse :
f(-2) = 3*(-2)² + 2*(-2) + 1 = 12 - 4 + 1 = 9
f(5) = 3*5² + 2*5 + 1 = 75 + 10 + 1 = 86
2) calculer f(1/2) et f(2/3)
f(1/2) = 3*(1/2)² + 2*(1/2) + 1 = 3/4 + 2/2 + 1 = 3/4 + 4/4 + 4/4 = 11/4
f(2/3) = 3*(2/3)² + 2(2/3) + 1 = 2/3 + 4/3 + 3/3 = 9/3 = 3
3) calcule f(√2) et f(√(3) + 2)
f(√2) = 3*(√2)² + 2√2 + 1 = 7 + 2√2
f(√(3) + 2) = 3*(√(3) + 2)² + 2(√(3) + 2) + 1
= 3(3 + 4√(3) + 4) + 2√(3) + 4 + 1
= 9 + 12√(3) + 12 + 2√(3) + 4 + 1
= 26 + 14√3