If m + n = 12 and n = 5, what is m-n? don't know the answer

2

Step-by-step explanation:

If m+n = 12 and we know what n is, then we can substitute n in to solve for m!

It would look like this:

m + 5 = 12

m = 12 - 5

m = 7

Next, we plug our numbers in for each variable in the next equation (m-n):

7 - 5

=

2

We need to find m first.

m+n=12, n=5 (plug in n as 5)

m+5=12 (subtract both sides by 5)

m=7

m-n: we know that m is 7 and n is 5

7-5=2

The final answer is 2.