Answer:
-7
Step-by-step explanation:
well, y-intercept is value of y when x = 0.
from the problem, we already have the answer, it is -7
but more detailed way is
m = -3
[tex] \frac{y - ( - 7)}{x - 0} = - 3 \\ y - ( - 7) = - 3x \\ y = - 3x - 7 \\ [/tex]
y-intercept is value of y when x = 0
[tex]y = - 3(0) - 7 \\ y = - 7[/tex]