Answer:
y=-5x-8
Step-by-step explanation:
the vertex form for a line is y=mx+b
m=slope, which is -5
so we know y=-5x+b for now
to figure out b, we use the coordinate (-3,7)
replace the x and y values: 7=-5(-3)+b
7=15+b
-8=b, and now the final equation:
y=-5x-8
