To determine the equation of the line that crosses trough the given points, use the following general equation of a line:
y - yo = m(x - xo)
where m is the slope of the line and (xo,yo) is a point of the line.
To calculate the m, use the following formula:
m = (y2 - y1)/(x2 - x1)
where (x1,y1) and (x2,y2) are two points of the line.
Replace (x1,y1) = (0,-1) and (x2,y2) = (-1,5) into the formula for m:
m = (5 - 0)/(-1 - 0)
m = -5
Next, replace this value and the point (xo,yo) = (0,-1) into the general equation and solve for y:
y - (-1) = -5(x - 0)
y + 1 = -5x
y = -5x - 1
Hence, the equation of the line is y = -5x - 1