Question

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

Answer 1

Answer : $Answer :f(x) = x^2 + 4x + 3 \ and \ f(x) = -2x^2 - 8x + 1$

Given: axis of symmetry of x = –2

To find axis of symmetry we use formula $x =\frac{-b}{2a}$

We check which equation has axis of symmetry x= -2

(1) $f(x) = x^2 + 4x + 3$

a=1 , b=4 so axis of symmetry $x =\frac{-4}{2*1} = -2$

(2) $f(x) = x^2 - 4x - 5$

a=1 , b=-4 so axis of symmetry $x =\frac{-(-4)}{2*1} = 2$

(3) $f(x) = x^2 + 6x + 2$

a=1 , b=6 so axis of symmetry $x =\frac{-6}{2*1} = -3$

(4) $f(x) = -2x^2 - 8x + 1$

a=-2 , b=-8 so axis of symmetry $x =\frac{-(-8)}{2*(-2)} = -2$

(5) $f(x) = -2x^2 + 8x - 2$

a=-2 , b=8 so axis of symmetry $x =\frac{-(8)}{2*(-2)} = 2$

So $f(x) = x^2 + 4x + 3$ and $f(x) = -2x^2 - 8x + 1$ has axis of symmetry x=-2

Answer 2

The answer is the first one and the fourth one