# How do you find the slope of a line parallel to the graph of each question y=3x-8?

Apr 1, 2015

Parallel lines have the same slope. Think slope as the angle between the line and the x-axis. So it makes sense that the slopes have to be equal.

$y$ is the line with a slope of $3$.

The standart form formula is $a x + b y = c$.

The slope is: $- \frac{a}{b}$

If you can't remember this, you can calculate the slope by selecting two random points on the line $y$.

$A = \left(0 , - 8\right)$
$B = \left(1 , - 5\right)$

The slope is: $\frac{- 8 - \left(- 5\right)}{0 - 1} = 3$

So any line with slope $3$ is parallel to the line $y$ (accept $y$ itself, it is called coincident line)

So we can say this:

A line is parallel to another if and only if their slopes are equal.