What is the equation of this line in slope-intercept form (-1,5) and (1,-3) ?

Slope intercept means

y=mx+c

the slope of the line is m = (y2-y1) / (x2-x1) = (-3-5) / (1+1) = - 4

the equation of the line is

y-5 = - 4 (x+1)

4x+y-1=0

changing the equation into slope intercept form

y = - 4x+1