= 6 + 3

= 9

So 9 is the y value when x = 3.

You can also graph the function i gave you and check at what “x value” the y value equals 9, and you’ll end up noticing 3 as the x value. So there r many ways to check ur answer.

Also, the most important thing to be noticed:

f(x) = y

f(x) = 2x + 3 is the same as writing y = 2x + 3

” f(x) = ” is another way of writing ” y = “, but its more accurate.

When u gonna take more higher level math courses, you’re often gonna use f(x) rather than y. In some cases you might use y, but f(x) is more helpful and accurate. It looks hard, but it really is a piece of cake. 🙂