What is the axis of symmetry for f (x) = 3 (x+4) ^2+1

Give that f (x) = 3 (x+4) ^2+1

This is a vertex form y=a (x-h) ^2+k

where:

a=3

h=4

k=1

since a is positive, the parabola opens up

the vertex is (4,1)

axis of symmetry is at x=-b/2a

f (x) = 3x^2+24x+49

thus

x = - (24/2*4) = - 4

thus the axis of symmetry is at x=-4