Answer:
The x value
Explanation:
Basically, the question is asking you to find the straight line distance from the y axis to a given point. The y-axis on a coordinate plane is the axis that goes up and down, and the x axis is the one that goes left and right. In a coordinate pair (x,y), x is how far left or right the point is and y is how far up or down it is. so the point (3,9) is three to the right and three up. (See screenshot)
So, the distance that (3,9) would be from the y-axis would be how far right it is, or x, which is 3!