Answer :
Isolate the variables. You want to get the five on the same side as the ten, so, you add five to both sides.
-4b+2b=15
-2b=15
b= -7.5
I believe. You may want to double check my work though.
-4b+2b=15
-2b=15
b= -7.5
I believe. You may want to double check my work though.