Hello there! Your answer is D, or y = 7.5x.
To find the slope, we abide by the formula:
m = rise/run
With this in mind, we can find the first complete point, which is (4,30). The rise, or y-value, is 30, and the run, or x-value, is 4. Therefore, the fraction of our slope is 30/4x.
However, we cannot end it here. 30/4 can be reduced by 2 to result in 15/2. We know that 15 divided by 2 gives us 7.5, because 14 divided by 2 gives us 7 and 16 divided by 2 gives us 8. That lets us know that when dividing 15 by another number, our slope is between 7 and 8.
Because 15/2 = 7.5 (or 7 1/2), our slope is:
y = 7.5x
Your answer is D.
Hope this helps!