SOMEONE PLEASE HELP ME ASAP

The line containing the midpoints of the legs of right triangle abc where a(-5,5), b(1, 1), and c(3, 4) are the vertices.

Acampus club held a bake sale as a fund raiser, selling coffee, muffins, and bacon and eggs sandwiches. the club members charged $1 for a cup of coffee, 3$ for a muffin , and $4 for a back. and egg sandwich. they sold a total of 55 items , easing $119. of the club members sold 5 more muffins than cups of coffee, how many bacon and egg sandwiches he’s did they sell

Whats are the trickiest steps to do when adding or subtracting rational expressions? how does knowledge of rational numbers u in adding and subtracting rational expressions?