Answer:
3x + y = -3
Explanation:
The slope-intercept form of an equation of a line:
![y=mx+b](https://img.qammunity.org/2020/formulas/mathematics/high-school/8nudzfk4b5l0arb9iixag2w8am6zn99zlr.png)
m - slope
b - y-intercept → (0, b)
The formula of a slope:
![m=(y_2-y_1)/(x_2-x_1)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/fc06wy5n2hf2a0hmyba6df4ibmxk1cn53a.png)
We have two points (-1, 0) and (0, -3) → b = -3.
Calculate the slope:
![m=(-3-0)/(0-(-1))=(-3)/(1)=-3](https://img.qammunity.org/2020/formulas/mathematics/high-school/qhwi62utvdwqqhx3plsixj00691y6rlgvg.png)
Finally we have the equation:
![y=-3x-3](https://img.qammunity.org/2020/formulas/mathematics/high-school/2715hymw9wxm3coz70h6ihj8bfwbljpmbi.png)
Convert it to the standard form (Ax + By = C):
add 3x to both sides
![3x+y=-3](https://img.qammunity.org/2020/formulas/mathematics/middle-school/9bk6vkspc83p9q3zbappf5osux3zjzw2p6.png)