Answer:
3x + y = -3
Explanation:
The slope-intercept form of an equation of a line:

m - slope
b - y-intercept → (0, b)
The formula of a slope:

We have two points (-1, 0) and (0, -3) → b = -3.
Calculate the slope:

Finally we have the equation:

Convert it to the standard form (Ax + By = C):
add 3x to both sides
