3. Helen of Troy was said to have been so beautiful that her face could launch a thousand ships. A table having this fable as its basis is shown here. Number of times Helen looked out her window, x Number of ships launched, y 1 2 3 4 1,000 2,000 3,000 4,000 a) Write a formula for this function. b) Solve the formula for x. c) How do x and y vary with respect to each other?