Answer:
![y=-3x+14](https://img.qammunity.org/2020/formulas/mathematics/middle-school/xrk7aegknrr8k5wh5xi5c3l8r46ea2t8tk.png)
Explanation:
Use slope intercept form.
![y=mx+b](https://img.qammunity.org/2020/formulas/mathematics/high-school/8nudzfk4b5l0arb9iixag2w8am6zn99zlr.png)
Where m is the slope and b is the y intercept.
We know the slope is -3 because it is given, so substitute it for m.
![y=-3x+b](https://img.qammunity.org/2020/formulas/mathematics/middle-school/ks44hnhociaegrv8ksv07q62tiw8u2u5vh.png)
Now we need to solve for b, and we can do this by plugging in the given point into our equation so far.
![-1=-3(5)+b \\ \\ -1 = b-15 \\ \\ b=14](https://img.qammunity.org/2020/formulas/mathematics/middle-school/spfomoli61pll7bqdvbqnidvylfsd53tov.png)
So our final equation will be
![y=-3x+14](https://img.qammunity.org/2020/formulas/mathematics/middle-school/xrk7aegknrr8k5wh5xi5c3l8r46ea2t8tk.png)