Answer:
A(8, 10)
Step-by-step explanation:
Vertex A is on the vertical line x=8, so we can find the y-coordinate by solving the boundary equation ...
5x +8y = 120
5(8) +8y = 120 . . . use the x-value of the vertical line
5 + y = 15 . . . . . . . divide by 8
y = 10 . . . . . . . . . . subtract 5
Point A is (8, 10).
