y=8x
a. (5,40) if x = 5 then y = 8(5) = 40. TRUE
b. (13,104) if x = 13 then y = 8(13) =104. TRUE
c. (9,72) if x = 9 then y = 8(9) = 72. TRUE
d. (64,8) if x = 64 then y = 8(64) = 512. FALSE
e. (72,9) if x = 72 then y = 8(72) = 576. FALSE
f. (120,15) if x = 120 then y = 8(120) = 960. FALSE
answer
a. (5,40)
b. (13,104)
c. (9,72)