# How do you graph -3x-9y=-18 using intercepts?

Jan 18, 2017

$\text{plot } \left(0 , 2\right) , \left(6 , 0\right)$

#### Explanation:

We can simplify the equation by multiplying through by - 1

$\Rightarrow 3 x + 9 y = 18$

To find the x-intercept substitute y = 0 into the equation and solve for x

$3 x + \left(9 \times 0\right) = 18 \Rightarrow 3 x = 18 \Rightarrow x = 6$

$\Rightarrow x = 6 \leftarrow \text{ is the x-intercept}$

To find the y-intercept substitute x = 0 into the equation and solve for y

$\left(3 \times 0\right) + 9 y = 18 \Rightarrow 9 y = 18 \Rightarrow y = 2$

$\Rightarrow y = 2 \text{ is the y-intercept}$

Plot the points (0 ,2) and (6 ,0), draw a straight line through them and you have the graph.
graph{-1/3x+2 [-10, 10, -5, 5]}