Solution: (1) The image is as shown in the figure. If you want to consider practical problems, you'd better draw it like this. If you think it is unnecessary, you can draw a straight line directly.

Note: the picture may not be standard enough. It is better to draw more parts with y greater than 0, and you need to adjust it yourself ~

(2) Let y=0 to get x=30 (as can be seen directly from the chart).

I hope it helps you (* _ _ *)? ~