Question

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

Answer 1

`"plot " (0,2),(6,0)`

Explanation:

We can simplify the equation by multiplying through by - 1

`rArr3x+9y=18`

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

`3x+(9xx0)=18rArr3x=18rArrx=6`

`rArrx=6larr" is the x-intercept"`

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

`(3xx0)+9y=18rArr9y=18rArry=2`

`rArry=2" 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]}