Answer
$f(x)=(x+2)^2-2$
Work Step by Step
Completing the square:
$f(x)=x^2+4x+2$
$f(x)=x^2+4x+(\frac{4}{2})^2-(\frac{4}{2})^2+2$
$f(x)=x^2+4x+2^2-2^2+2$
$f(x)=(x+2)^2-4+2$
$f(x)=(x+2)^2-2$
Graphing the function:
1st step (black graph): The parent function: $y=x^2$
2nd step (green graph): Shift down by 2 units. $y=x^2-2$
Final step (blue graph): Shift left by 2 units. $y=(x+2)^2-2$