identify the axis of symmetry for the graph of f(x) = -2(x - 2)2 -4

Question

cwrw238 · Answer

for -a(x -b)^2 - c  the axis of symmetry is x = b

so if you compare this with your equation you will get what you want

ahsome · Answer

@cwrw238 @fani1996
Equation: $f(x)=-2(x-2)^2-4$
Expand first:
$$f(x)=-2(x-2)^2-4$$
$$f(x)=-2(x-2)(x-2)-4$$
$$f(x)=-2(x^2-4x+4)-4$$
$$f(x)=-2x^2+8x-8-8$$
$$f(x)=−2x2+8x-16$$
Equation for axis of symmetry: $$\frac{-b}{2a}$$
Sub in the values, $a=-2, b=8$
$$\frac{-b}{2a}$$
$$=\frac{-1*8}{2*-2}$$
$$=\frac{-8}{-4}$$
$$=2$$
Therefore, the axis of symmetry is 2

anonymous · Answer

thanks :)

ahsome · Answer

No problem @fani1996. If you think I helped, please press the Best Response button. Thank you :)