What is the equation of a line with given intercepts?

[MoreZitiPlease]

Homework Statement

write an equation of the line:

y intercept: negative 2
x intercept: negative 1

Homework Equations

y

The Attempt at a Solution

i know its y equals mx plus b

So b would equal negative two, but what about the y and the slope

 

[CompuChip]

The x-intercept is the point where y = 0. In this case, that is at x = -1. If you plug that information into the general formula you will get an equation just for m.

 

[nicksauce]

The slope, m, is the change in y divided by the change in x between two points (rise over run). You have two points, so you can find the slope.

 

[tiny-tim]

[y intercept: negative 2
x intercept: negative 1
…
i know its y equals mx plus b

Hi MoreZitiPlease!

If you're not sure, write out the known coordinates:

You know (0,-2) and (-1,0) are on the line.

So -2 = m.0 + b

0 = m.(-1) + b.

 

[symbolipoint]

Standard Form equation for a line: Ax + By = C.

You already have two points and they are the axes intercepts.
A*0 + B*(-2) = C;
A*(-1) + B*0 = C,
But those might not help you since you get one equation with two unknowns.
YOUR INERCEPTS are (0, -2) and (-1, 0), so just resort to y=mx+b general form and find the slope using the known points. Since you already have the y intercept, you can now plug all information into the general form.