It will be more common in our study of algebra that we do not know the value of the variables. In this case, we will have to simplify what we can and leave the variables in our final solution. One way we can simplify expressions is to combine like terms. Like terms are terms where the variables match exactly (exponents included). Examples of like terms would be `3xy` and `− 7xy` or `3a2b` and `8a2b` or `− 3` and `5`. If we have like terms we are allowed to add (or subtract) the numbers in front of the variables, then keep the variables the same. This is shown in the following examples Example `5x − 2y − 8x + 7y`

	`5x − 2y − 8x + 7y`
Combine like terms	`=(5x − 8x)+(− 2y + 7y)`
Solution	`=− 3x + 5y`

Example `8x^2−3x+7−2x^2+4x−3`

	`8x^2−3x+7−2x^2+4x−3`
Combine like terms	`=(8x^2−2x^2)+(−3x+4x)+(7−3)`
Solution	`=6x^2 + x + 4`