M+7=3+m+4 solve for m

Remember you can do anything to an equaiton as long as you do it to both sides

m+7=3+m+4

m+7=m+3+4

m+7=m+7

minus 7 from boths ides

m=m

this is true

therefor all real numbers will work for m

m=all real numbers

M+7=3+m+4

Combine like-terms

0m=0

M is ARN (All Real Numbers)