Answer: 1
Step-by-step explanation: To solve this problem, let's graph the line.
It's important to understand that the y-intercept is the point where the line crosses the y-axis.
So if our line has a y-intercept of 3, it crosses the y-axis up 3 units. So we start this problem by plotting the point (0,3) which I labeled point A.
From there, our slope of -3 can be thought of as -3/1 so we go down 3 units and to the right 1 unit and plot point B. Notice that point B happens to lie on the x-axis at (1,0) and remember that the x-intercept is the point where the line crosses the x-axis. Since our line crosses the x-axis at the point (1,0), it has an x-intercept of 1.
If you're given a y-intercept and a slope like you are in this problem, you won't always be able to determine the x-intercept but things work out nicely here because point B happens to lie on the x-axis.