which functions have an axis of symmetry of x = -2? check all that apply.\n□ f(x)=x^{2}+4x + 3\n□…

which functions have an axis of symmetry of x = -2? check all that apply.\n□ f(x)=x^{2}+4x + 3\n□ f(x)=x^{2}-4x - 5\n□ f(x)=x^{2}+6x + 2\n□ f(x)=-2x^{2}-8x + 1\n□ f(x)=-2x^{2}+8x - 2
Answer
Explanation:
Step1: Recall axis - of - symmetry formula
For a quadratic function $f(x)=ax^{2}+bx + c$, the axis of symmetry is given by $x =-\frac{b}{2a}$.
Step2: Check $f(x)=x^{2}+4x + 3$
Here $a = 1$, $b = 4$. Then $x=-\frac{4}{2\times1}=- 2$.
Step3: Check $f(x)=x^{2}-4x - 5$
Here $a = 1$, $b=-4$. Then $x=-\frac{-4}{2\times1}=2$.
Step4: Check $f(x)=x^{2}+6x + 2$
Here $a = 1$, $b = 6$. Then $x=-\frac{6}{2\times1}=-3$.
Step5: Check $f(x)=-2x^{2}-8x + 1$
Here $a=-2$, $b=-8$. Then $x=-\frac{-8}{2\times(-2)}=-2$.
Step6: Check $f(x)=-2x^{2}+8x - 2$
Here $a=-2$, $b = 8$. Then $x=-\frac{8}{2\times(-2)} = 2$.
Answer:
$f(x)=x^{2}+4x + 3$, $f(x)=-2x^{2}-8x + 1$