Question

Let f(x)=4x+9. Write a function g whose graph is a reflection in the y-axis of the graph of f. g(x)= ?

Answer 1

`g(x)=-4x+9`

Explanation:

So we know that:

`f(x)=4x+9`

To reflect across the y-axis, instead of x, use -x. Therefore:

`g(x)=f(-x)=4(-x)+9`

Simplify:

`g(x)=-4x+9`

And that's our answer :)