Answer:
y = -x +4
Explanation:
The y-intercept of the line is at +4, so the only viable choice is the last choice.
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Each of the equations is shown in slope-intercept form:
y = mx + b
where b is the y-intercept, the y-value when x=0. The graph shows that as point (0, 4). So, the equation you're looking for is ...
y = (some x-term) +4
If you want to spend more brain power on the problem, you can compute the slope of the line as ...
m = ∆y/∆x = (1-4)/(3-0) = -3/3 = -1
Now, you know for sure the equation of the line is ...
y = -x +4