Students sold raffle tickets to raise money for a field trip. the first 20 tickets cost $4 each. to sell more tickets, they lowered the price to $2 each. if they raise $216, how many tickets did they sell in all?

The input to the function is x and the output is y. write the function such that x can be a vector (use element-by-element operations). a) use the function to calculate y(-1.5) and y(5). b) use the function to make a plot of the function y(x) for -2 ≤ x ≤ 6.