Graphing Linear Equations: 2x + 6y = -18

Write the equation in Slope Intercept form; identify the slope:

2x + 6y = -18

I do not understand how to tell why some equations you do not have to get rid of the 6 in front of the Y but in others like this one you do. If that makes sense

For example you have to divide all this by 6 to get the slope m = -1/3
However how come for a problem like this you don't have to do anything like that x + 2y = 8

If you could please explain why this is I would appreciate it

Thanks

Re: Graphing Linear Equations

Stumped x said:

2x+6y = - 18

Click to expand...

There is a reason why you studied equations and solving equations. Those are the skills you need here. You must put it in slope-intercept form. It won't do it by itself.

2x + 6y = -18

ALWAYS (almost) remove common factors.

Divide by 2

x + 3y = -9

Get 'y' alone

Subtract 'x'

3y = -x - 9

Divide by 3

y = -(1/3)x - 3

Slope = -1/3
y-Intercept: (0,-3)

Stumped x said:

However how come for a problem like this you don't have to do anything like that x + 2y = 8

Click to expand...

YES, you do!
2y = -x + 8
Now you need to divide by 2, right :idea: