Answer:
a) 6/9 shaded.
b) About 67% is shaded. (66.6% repeating rounded to 67%)
Another way to say f(x) is y, so y=0 at -2 and 10. :)
Keep adding 5 to the first term as many times as you need. 15-10=5. So if you add 15 then subtract 10, you are really just adding 5 to 4 first =9,14,19, etc
