Igot 6.8 idk what i did wrong i have no idea

Which expression do you get when you eliminate the negative exponents of 4a^2 b^216a^-3 b

Tom can paint the fence in 12 hours, but if he works together with a friend they can finish the job in 8 hours. how long would it take for his friend to paint this fence alone?

Which expression and diagram represent “renee biked four times as far this month as last month”?