I'm guessing the question is "what's the equation"?
When slope and 1 point are known
Since it is a y-intercept then x=0 and the point is
(0,5)
b = y - mx
b = 5 --3 * 0
b = 5
Then we enter the slope and value of "b" into this equation
y = mx + b
y = -3x + 5