How to simplify the expression by combining like terms

-r+6+8r-14
-r     -r
6+7r-14
+6     +6
7r-8

It is 7r-8 because you combine like terms

-r + 6+8r-14
You subtract r to 8r which is 7r

So now it is 7r + 6 - 14

Then you add 6 to -14 which is -8

And you get 7r -8