Question

What is the equation of the following line written in general form? (The y-intercept is 7.)

Answer 1

3x - y + 7 = 0

Explanation:

The slope-intercept form of an equation of a line:

`y=mx+b`

m - slope

b - y-intercept

Put the given y-intercept b = 7 and the coordinates of the point (-2, 1) to the equation:

`1=-2m+7` subtract 7 from both sides

`-6=-2m` divide both sides by (-2)

`3=m\to m=3`

We have the equation:

`y=3x+7`

Convert it to the general form
`Ax+By+C=0`:

`y=3x+7` subtract 3x and 7 from both sides

`-3x+y-7=0` change the signs

`3x-y+7=0`