What is -25 + 25+ -871+ 92+ -2282+ 3y +3y

Don't know how to find x given these segment lengths

What is the length of the midsegment of a trapezoid with bases of length 15 and 25 ?

You just purchased two coins at a price of $670 each. because one of the coins is more collectible, you believe that its value will increase at a rate of 7.1 percent per year, while you believe the second coin will only increase at 6.5 percent per year. if you are correct, how much more will the first coin be worth in 15 years?