Please solve this in desperate need

Simplify (a/b - b/a) times (a - a^2/a+b) a - a^2/a=b is a mixed number

Fractions can be added and subtracted only if they're fractions. a. like b. proper c. improper d. unlike

Two trains leave stations 546 miles apart at the same time and travel toward each other. one train travels at 95 miles per hour while the other travels at 115 miles per hour l. how long will it take for the two trains to meet