The equation is in slope-intercept form, so you can read the equation to find the y-intercept is (0, -1).
Since the slope is -1/2, the graph goes up 1 unit for each 2 units to the left. The x-axis is up 1 unit from the y-intercept, so the x-intercept is 2 units to the left of x=0, at (-2, 0).
The graph is the line that goes through the points (0, -1) and (-2, 0).
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If you like, you can put the equation into intercept form, which shows you both the x- and y-intercepts at once. That form is ...
... x/a + y/b = 1
where a and b are the x- and y-intercepts.
If we add 1-y to the given equation, we have ...
... 1 = (-1/2)x - y
... 1 = x/(-2) + y/(-1) . . . . intercept form
