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MoreZitiPlease
Aug25-08, 02:38 PM
1. The problem statement, all variables and given/known data

write an equation of the line:

y intercept: negative 2
x intercept: negative 1

2. Relevant equations
y


3. 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
Aug25-08, 03:20 PM
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
Aug25-08, 03:21 PM
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
Aug25-08, 04:41 PM
[y intercept: negative 2
x intercept: negative 1

i know its y equals mx plus b

Hi MoreZitiPlease! :smile:

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. :smile:

symbolipoint
Aug25-08, 09:15 PM
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.