Question

considere a funçao dada por f(x)=x2+2x determine f(x)=3 f(x)=0 f(-2)

Answer 1

f(x)= 3 --> 3=x^2 + 2x
x^2 + 2x - 3 = 0
Δ= 4 + 12 = 16
x' = -1 - 2 = -3
x''= -1 + 2 = 1
======================
f(x)= 0 --> x^2 + 2x = 0 
x(x + 2)=0
x'=0
x''= -2
=========================
f(-2)= (-2)^2 + 2.(-2)
= 4 - 4 = 0