3. Juanita wants to buy a computer. She needs to earn at least 400 dollars. If she makes 9
dollars an hour and has already saved 40 dollars, how many hours does she need to
work?
9x + 40 = 400 (with x being how many hours she has worked). We get rid of the 40 on both sides by subtraction. Our new equation is 9x = 360. Now we divide 9 on both sides and we learn that x = 40.