Answer:
[tex]\large\boxed{y+7=-3(x-5)}[/tex]
Step-by-step explanation:
[tex]\text{The point-slope form of an equation of a line:}\\\\y-y_1=m(x-x_1)\\\\m-slope\\(x_1,\ y_2)-point\\\\\text{We have}\ m=-3\ \text{and}\ (5,\ -7).\\\text{Substitute:}\\\\y-(-7)=-3(x-5)\\y+7=-3(x-5)[/tex]