what is the equation of the blue line? (see photo)

Answer:
y= -x-1
Step-by-step explanation:
(x1,y1) = (-1,0) ; (x2,y2) = (0,-1)
y=mx+b
m=[tex]\frac{y2-y1}{x2-x1}[/tex]=[tex]\frac{-1-0}{0-(-1)}[/tex]=[tex]\frac{-1-0}{0+1}[/tex]=[tex]\frac{-1}{1}[/tex]=-1
Then substitute either x1y1 or x2y2 (it's gonna give the same answer anyways) and m to find b.
y=mx+b
0=(-1)(-1)+b
0=1+b
0-1=1-1+b
b=-1
Then substitute b and m to get the equation.
y=(-1)x+(-1)
y= -x-1