For which function does f(14)=23?

Question

For which function does f(14)=23?

f(x)=x+9

f(x)=14x+23

f(x)=12x−20

f(x)=3x−7

I cannot seem to remember how to figure a question like this out.

Answer 1

You just need to plug in 14 for x in each of the equations and see which one is 23.

For the first one, (14) + 9 = 23 so that works.

For the second one, 14(14) + 23 = 196 + 23 = 219 so that does not work

For the third one, 12(14) - 20 = 168 - 20 = 148 so that does not work

For the last one, 3(14)-7 = 42-7 = 35 so that does not work