The value is 5, the steps above are correct
We have this equation for the slope is: y=mx+b which m is the slope and b is the y-intercept, so we have y=20-15x or y=-15x+20, and we already know that the slope is -15 and y-intercept is 20. As a result, the student's error is that he thinks that 20 is the slope because it is the first number. Hope it help!
Answer:
Answer should be 5/2 I thinkkkkk
