Answer:
![y=-3x](https://img.qammunity.org/2021/formulas/mathematics/high-school/wisubq8fwp3zt0nu4l01h3fjjmmkhcd3zw.png)
Explanation:
We want to write the equation for a line that has a slope of -3 and passes through (-1, 3).
So, we can use the point-slope form:
![y-y_1=m(x-x_1)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/ks7lzc9jj3emt3ptrdvrvr0uzhz4c0qyo5.png)
Where m is the slope and (x₁, y₁) is a point.
Let's let (-1, 3) be (x₁, y₁) and let's substitute -3 for m. This yields:
![y-3=-3(x-(-1))](https://img.qammunity.org/2021/formulas/mathematics/high-school/kkq9y2p5mjiqrv05w0e32ple9l97osl9d9.png)
Simplify:
![y-3=-3(x+1)](https://img.qammunity.org/2021/formulas/mathematics/high-school/kuo7ap8s14zavwr1t3jfvw1b6gejun2bvp.png)
Distribute on the right:
![y-3=-3x-3](https://img.qammunity.org/2021/formulas/mathematics/high-school/n9bva63b5z96gfy9bbgnfv7kft3uy2oxc8.png)
Add 3 to both sides. So, our equation is:
![y=-3x](https://img.qammunity.org/2021/formulas/mathematics/high-school/wisubq8fwp3zt0nu4l01h3fjjmmkhcd3zw.png)
And we're done!