To simplify this problem we need to combine like terms.

Simplify the following expression:

We can only subtract variables with the same exponent.

In this case, we can only combine the first two terms.

To do so, keep the exponents the same and subtract the coefficients.

So our answer is:

To simplify this problem we need to combine like terms.

Simplify the following expression:

Let's begin by subtracting the 12y

From here, our answer should be apparent:

So our answer is just 0

Group and collect like terms:

Group and collect like terms:

Simplify the following expression:

Now, to complete this, we need to realize that we can only subtract variables with the same exponent.

In this case, we can only combine our first two terms, because they both have an exponent of 7. The third term has an exponent of 8, so it cannot be combined and must be left as is.

So, our answer must be:

To simplify this problem we need to combine like terms.