Pls find 5he area of each rectangle thxs

Solve the following pair of equations for x and y: ax/b_ by /a= a +b; ax - by = 2ab

Out of 50 students surveyed, 16 have a dog. based on these results, predict how many of the 280 students in the school have a dog.

I'm at a bookstore with $\$35$ in my pocket and a $20\%$-off coupon. what is the cost of the most expensive book i can buy with my money and the coupon? (assume that there are books of every possible price in the bookstore. it's a large bookstore! )