Which functions have an axis of symmetry of x = –2? Check all that apply.

f(x) = x2 + 4x + 3
f(x) = x2 – 4x – 5
f(x) = x2 + 6x + 2
f(x) = –2x2 – 8x + 1
f(x) = –2x2 + 8x – 2

Question

Which functions have an axis of symmetry of x = –2? Check all that apply.

f(x) = x2 + 4x + 3
f(x) = x2 – 4x – 5
f(x) = x2 + 6x + 2 
f(x) = –2x2 – 8x + 1
f(x) = –2x2 + 8x – 2

HighIQReptilian · Answer

Ok. So, are you aware of the effects that the a,b, and c have on the graph of an equation? Also, are the 2s following the xs ^2 or what?

ashlynnloper · Answer

yes the 2's are following the x's

HighIQReptilian · Answer

So, per usual, are you allowed desmos?

ashlynnloper · Answer

yes

HighIQReptilian · Answer

Ok, well that would make it quite easy. Nonetheless, however, I will tell you how to solve this. So, in order to find the x coordinate of the vertex you have to divide b(4) by two(2).

HighIQReptilian · Answer

This is in reference to the first one. woopsie I forgot! it is divided by negative 2 not positive.

HighIQReptilian · Answer

The complete formula is -(b/2a) In the case of the first one, a=1 and b=4. therefore the filled in equation is -(4/2)= (your cue.)

HighIQReptilian · Answer

@ashlynnloper does this make sense?

ashlynnloper · Answer

freakkkkkk yessss!!!!!

HighIQReptilian · Answer

Lol! Glad it does :D