Hey there! :)
Let's put all of our facts down first. We know that slope-intercept form is y=mx+b , where m=slope & b is the y-intercept.
So, if we're given the slope and y-intercept, then we can very simply plug those values into slope-intercept form!
Our slope is 4 and our points are (0, -1).
y = mx + by = (4)x + (-1)
Get rid of our parenthesis.y = 4x - 1
So, our equation of the line that passes through (0, -1) and has a slope of 4 is y = 4x - 1
~Hope I helped!~