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

1 Answer
Jun 15, 2015

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)