Answer: c=35
Step-by-step explanation:
to find the slope, you do y2-y1/x2-x1. So you will set up your equation like this:
25-c/21-15 = -5/3
this slope has been simplified by dividing by 2, because 21-15=6 and they simplified it to 3. So the original answer for 25-c was -10. So this means that c=35.
