# Cant remember how to use formula

1. Oct 2, 2006

### lostit

Cant remember how to use formula !!!

i cant for the life of me remember which way to do this formula someone please show me the light,,,,,
to find the slope(m) of the line you have y2 - y1 / x2 - x1 am i right then getting the result (m) you use this formula y=mx+c
taking y1 for y and x1 for x ,
now heres my question
we have c = (m)(x) is it - y or is it /y

2. Oct 2, 2006

$$m = \frac{y_{2}-y_{1}}{x_{2}-x_{1}}$$ $$y = mx+c$$ then $$c = y_1-mx_1$$

Last edited: Oct 2, 2006
3. Oct 2, 2006

### xAxis

y=mx + c is the equation of the line. Here x and y are coordinates of any point on that line.
(y2-y1)/(x2-x2) will give you the slope m. Here x1 y1, x2 y2 are coordinates of two particular points.
Your question makes no sense, as c is not equal to (m)(x)

4. Oct 2, 2006

$$c = -mx_{1}+y_{1}$$.