How do you write the inverse of the function y=x-12?

1 Answer
Jun 23, 2016

x=y+12.

Explanation:

A function is a relationship between two variables.

For example your function is y=x-12.
It means that if I give a number to x I obtain a number for y.
Let's try:

if x is 23, y is y=23-12=11.

When you invert the function you want to invert the relationship between the two variables. You insert a value for y and you get the value of x.

Let's try: if y=24, what is x?

The relationship is

24=x-12.

We can solve this adding 12 on both sides

24+12=x-\cancel12+cancel12

36=x.

It seems that the inversion was done adding 12 on both sides.
We can generalize this to the initial equation

y=x-12

if we add 12 on both sides we have

y+12=x-cancel12+cancel12

y+12=x.

This relationship tell us that for each value we assign to y we obtain the value of x. That is exactly the inverse of the original function.