Find m1 and m2 ,please I really need this answer it’s so confusing

Which simplifys to a+ b? a-(1-b)+1 -(1-a)-b+1 (a--1) -1)+1

Factor the expression using the gcf. the expression 21m−49n factored using the gcf

Timmy uses 1 1 2 cups of sugar for every 2 gallons of lemonade he makes. how many cups of sugar would timmy use if he makes 13 gallons of lemonade?