Question

How do you write an equation of a line that goes through (-3,-1) and (-8,-4)?

Answer 1

First, find the slope. The formula for slope is m = `(y_2 - y_1)/(x_2 - x_1)`, where m represents slope

Explanation:

m = `(-4 -(-1))/(-8-(-3))`

m = `-3/-5`

m = `3/5`

Now that we know that the slope is `3/5`, we can use point slope form to find the slope intercept equation of the line. The point slope form formula is:

`y - y_1 = m(x - x_1)`

Pick one of the points to plug in for (`x_1, y_1`). I'll pick (-3,-1), but the other one would give you the same answer.

y - (-1) = `3/5`(x - (-3))

y + 1 = `3/5x` + `9/5`

y = `3/5x` + `(9 - 5)/5`

y = `3/5x` + `4/5`

The slope is `3/5` and the y intercept is `4/5`.