Question

How do you find the slope of a line parallel to `3x`+y=15`?

Answer 1

`m=-3`

Explanation:

Explicit the equation:

`y=-3x + 15`

Since every parallel line is of the form `y=-3x + q`, we have its slope is always `m=-3`

(To prove this, you might consider an `m` such that `-3x + 15 -mx - q=0` has no solution for every `q!=15`, it is pretty obvious you have to consider the only m such that -3-m=0, or you will have a linear equation which has always a solution)