Answer:
15
Step-by-step explanation:
I used system of equations so to set it up I chose two points on the graph luckily this one is easy so there are some exact points (and you don't really need the system since it is a straight line and not exponential):
2x = 30; x = 15
4x = 60 ; x = 15
15 x (x-axis value) = y axis value
