Question

How do you graph `3x+y=-6`?

Answer 1

Change the equation into standard form, `y = mx + c`
Then either plot points or use the y-intercept and the gradient.

Explanation:

The y-intercept is -6. This is the first obvious point.
To find the x-intercept, make y = 0:
`0 = -3x - 6 rArr 0 = 3x + 6`
Now solve for x: `3x = -6, rArr x = -2`

These two points are enough,but it is better to have a few more to check.

The gradient is -3. This is better written as `(-3)/1`

From -6 on the y-axis, count UP 3 units and LEFT 1 unit and mark the point. (-1,3). Repeat this a few times which will give the points
(-2, 0), (-3,3) (-4,6) (-5,9)

These can be joined with a straight line to give the graph.