Answer:
r = 1
Step-by-step explanation:
slope = change in y / change in x, so:
change in y / change in x = 2/3
5 - r / 7 - 1 = 2/3
5 - r / 6 = 2/3
now solve this equation.
first, multiply both sides by 6 to get rid of the fraction:
subtract 5 from both sides
multiply both sides by -1