Answer:
11m + 10r.
Step-by-step explanation:
First see which numbers in the equation share the same variable (letter).
If two numbers don't share a variable, they cannot combine.
First, let's add and subtract the numbers with alike variables.
You will know whether to add or subtract by looking at the sign in front of each number. Example, when you're looking to take out the m numbers, you have to pick them out like how they are in bold below.
15m+5r+18r-5r+2m-8r-18m+12m.
Notice how the signs in front of the numbers are also bold. That's how you determine whether to add or subtract.
If you use that example, you'll get this equation:
15m + 2m - 18m + 12m.
In total, that adds up to 11m.
Now we have the r variable.
5r + 18r - 5r - 8r.
That totals to 10r.
Now you're left with 11m + 10r.
Since these have two different variables, they cannot be added together. Therefore, that is your final answer.
