Question

The graph of y = 2^x and the graph of y = 2^-x are symmetrical. What is the line of symmetry?

Answer 1

The equation of the line of symmetry is x = -b/2a

So one way to do this is put your equation into ax^2 + bx + c form:

So expand:

y = -2(x^2 + -2x + 1) +3 Now simplify:
y = -2x^2 + 4x +1

Now you have a= -2, b=4, c=1

So plugging these into the equation for the line of symmetry:

x = -4/2(-2)
x = 1 is your equation.

Ignore the previos answers.

Answer 2

My options are as follows:

the x-axis
y = x
the y-axis
y = -x