Sarah's parents purchased a refrigerator for $320. If sales tax is 7% of the cost, how much tax did Sarah's parents pay for the refrigerator?

22.4 is the answer 7% of the cost is 22.4.

yes because there is exactly one y value for every x value

for function there can't be more than one value for every x value

look at the picture.

y-intercept for the function on a picture is 4 → point (0, 4).

y-intercept for the function

is for x = 0. substitute:

y-intercept is 8 → point (0, 8).