The answer is $29.99. First, you add $10 to $49.98 which equals 59.98. Next, set up a proportion: x over 59.98 equals 50 over 100. 59.98 times 50 equals 2,999. Now divide 2,999 by 100 and you get your answer.
The y-intercept is where the graph goes through the y-axis (the vertical line in the center). It goes through at y=-9, so the coordinates would be (0,-9), since it is (x,y).
