The base of an isosceles triangle is 7cm long. Each of the other two sides is x cm long. What will be the expression for its perimeter

Samantha swam upstream for some distance in one hour. she then swam downstream the same river for the same distance in only 12 minutes. if the river flows at 4 mph, how fast can samantha swim in still water?

Ineed with math stuff it involves graphs

What is the sum of these mixed numbers 4 2/3+ 3 1/9