The complete question is: Write an equation in slope-intercept form through (3,-1) with a slope of -2.
Considering the definition of a line, the equation of the line that passes through the point (3, -1) and has a slope of -2 is y= -2x + 5.
Linear equation
A linear equation o line can be expressed in the form y = mx + b
where
- x and y are coordinates of a point.
- m is the slope.
- b is the ordinate to the origin and represents the coordinate of the point where the line crosses the y axis.
Line in this case
In this case, you know:
The line has a slope of -2.
The line passes through the point (3, -1).
Substituting the value of the slope m and the value of the point in the expression of a linear equation, the value of the ordinate to the origin b can be obtained:
-1= (-2)×3 + b
-1= -6+ b
-1 +6= b
5= b
Finally, the equation of the line that passes through the point (3, -1) and has a slope of -2 is y= -2x + 5.