Cause it has a slope of -3/2, we could call its equation: y= -3/2x+b
and we have to find out b
In addition, it has a y-intercept of -1, that means this line goes through the point A(0;-1). So we could replace x=0 and y= -1: -1 = -3/2x0+b and we have b= -1
We obtain the equation: y= -3/2x-1