С-10+15-с; x+y+x+x-y; a-3+b+3; m+m+1+m-20.

Question

С-10+15-с; x+y+x+x-y; a-3+b+3; m+m+1+m-20.

Answer 1

C+5-c=5
3x+y-y=3x
a+b-3+3=a+b
2m+1+m-20=3m+1-20=3m-19