What does it mean for 2 expressions to be equivalent

Divide. reduce the answer to lowest terms.5 2/3 ÷ 3 1/9

Use composition to determine if (x) or h(x) is the inverse of f(x) for the limited domain x2-1.

Fatima plans to spend at least $15 and at most $20 dollars on sketch pads and pencils. if she buys 2 sketchpads, how many pemcils can she buy while staying in her price range? fatima can buy between and pencils. ? (type whole numbers. use ascending? order.)