Midpoint formula
Let S denote the midpoint of R and T
x+y=987
x=y+37
2y+37=987
2y=950
y=475
The cost of the dryer is 475.
So right now you see that you have x and y intercept right? Then plug those intercepts in equation that you have and solve for z. Which means z=5(1)(1) will be 5, 5(4)(1) will be 20, and 5(1)(2) will be 10. So, overall you have 5, 20, 10.
25, and 12.5... it is dividing by a half each time, so half of 50 is 25 and half of 25 is 12.5, hope this helps!