Answer:
D
Step-by-step explanation:
A function is any line that does not repeat in x-value (doesn't repeat on the x-axis).
18
48-12 = 36
36/2
y = 70 and x = 20
180 - 40 = 140
140/2 = 70
70 + 90 = 160
180 - 160 = 20
