Answer:
Step-by-step explanation:
The equation of a line in slope-intercept form is given by
![y=mx+b](https://img.qammunity.org/2023/formulas/mathematics/high-school/smsb8cbft03lwblmi49nf2l6jby2ofxzws.png)
where m is the slope and b is the y-intercept.
Now, we know that the slope is m = -3; therefore, the above equation becomes
![y=-3x+b](https://img.qammunity.org/2023/formulas/mathematics/college/4sbwu75cfh7n19kjzr6rp2h698eh3vse7u.png)
Now we need to find the y-intercept b and we do this using the point (1, -7).
Now, from the point (1, -7 ) we know that when x = 1, y = -7; therefore, the above equation gives
![-7=-3(1)+b](https://img.qammunity.org/2023/formulas/mathematics/college/jwz16d37lh7djkkb21fe8182w797njna97.png)
![\rightarrow-7=-3+b](https://img.qammunity.org/2023/formulas/mathematics/college/ntisged137dteiqy4ubsrwi11y7n5i5ed6.png)
Adding 3 to both sides gives
![-7+3=-3+b+3](https://img.qammunity.org/2023/formulas/mathematics/college/q2ecp7yqu8792w2pyph8lcywvoohb85d7q.png)
![-4=b](https://img.qammunity.org/2023/formulas/mathematics/college/sz532ee78db9z842fpspr3njip18x3x0fd.png)
With the value of b in hand, we now write our equation as
![y=-3x-4](https://img.qammunity.org/2023/formulas/mathematics/college/4grex72c9j8xcubnvaxgfy4fpglt6c15oy.png)
which is our answer!