Question

How do you write an equation of a line with Slope =3,(4,-8)?

Answer 1

`y+8=3(x-4)`
or in standard form `3x -1y = 20`

Explanation:

Given a slope of `m=3` through a point `(hatx,haty)= (4,-8)`
the slope-point form of a line:
`color(white)("XXXX")` `(y-haty) = m (x-hatx)`
becomes
`color(white)("XXXX")` `y-(-8) = 3 (x-4)`
or
`color(white)("XXXX")` `y+8 = 3(x-4)`

While this is a perfectly correct answer, an equation in standard form might be more desirable.

`color(white)("XXXX")` `y+8= 3x -12`

`color(white)("XXXX")` `-3x+y+8 = -12`

`color(white)("XXXX")` `-3x+y = -20`

`color(white)("XXXX")` `3x-y = 20` (in standard form)