Answer:
y = -2x + 1
Step-by-step explanation:
The slope-intercept form of an equation of a line:
[tex]y=mx+b[/tex]
m - slope
b - y-intercept
The formula of a slope:
[tex]m=\dfrac{y_2-y_1}{x_2-x_1}[/tex]
We have two points (1, -1) and (2, -3).
Substitute:
[tex]m=\dfrac{-3-(-1)}{2-1}=\dfrac{-2}{1}=-2[/tex]
Put it and the coordinates of the point (1, -1) to the equation of a line:
[tex]-1=-2(1)+b[/tex]
[tex]-1=-2+b[/tex] add 2 to both sides
[tex]1=b\to b=1[/tex]
Finally:
[tex]y=-2x+1[/tex]
