Question

Which of the following is a reflection of the graph of y=f(x) in the y-axis?

y= -f(x)

y= f(-x)

y= |f(x)|

y= f(|x|)

y= -f(-x)

is it the last one?

Answer 1

A reflection of the graph is an exact opposite graph across either the x axis or y axis.

Answer 2

In this case it is the y axis, which looks like a diagonal line with a positive slope. In order to create the reflection, you would have to inverse that.

If it was -f(-x), the graph would be the same because - times a - = a +
You are on the right track though.

How do you feel about choice B?
It is similar to choice A but this one gives the opposite - slope that you need.

Answer 3

I guess that's correct. I thought the opposite meant they'd both be negative

Answer 4

That is very reasonable.
If you graph y = f(x) and y = f(-x) along with the other choices you will see the choices that are given visually. This might be helpful in understanding this concept. Remember that the problem asks you to find the reflection of the y axis.