Find the equation of the straight line that passes through the points (−1, 5) and (5, −1). Find the coordinates of the point where this line crosses the y-axis

slope is m= -1-5/5+1

The y intercept or b is the other thing you need to know. (0,?)

y=mx+b

you could use the point slope

y-y1=m (x-x1)