3x - 9y = 3 and 6x - 3y = -24

Solve and please tell me which method you used.

Question

3x - 9y = 3 and 6x - 3y = -24

Solve and please tell me which method you used.

shamil98 · Answer

3x - 9y = 3
6x -3y = -24

let's use elimination, divide the second equation by -3.

your two new equations are:

3x - 9y = 3
-3x + y = 8

combine and solve for y now.

anonymous · Answer

So I divide 8 by -3?

shamil98 · Answer

you add the equations together..

anonymous · Answer

Oh Oh I see

shamil98 · Answer

you  could do substitution as well.
3x - 9y = 3
3x = 9y + 3
x = 3y + 1

6(3y+1) -3y = -24

shamil98 · Answer

ah i made an error with the first method

shamil98 · Answer

3x - 9y = 3
6x -3y = -24

you would divide by -2 not -3, my bad.

3x - 9y = 3
-3x +3/2y = 12

shamil98 · Answer

anyways, just use substitution, it'll be easier..

shamil98 · Answer

3x - 9y = 3
6x -3y = -24

3x - 9y = 3
x = 3y + 1

x = 3y + 1
6x -3y = -24

6(3y + 1)  -3y = -24
What do you get?

anonymous · Answer

18y + 6 - 3y = -24
15y + 6 = -24
15y = -30
y = -2

anonymous · Answer

Err idk if I'm correct

shamil98 · Answer

yeah you're right now plug back in y and solve for x..
x = 3y + 1

anonymous · Answer

x = -5?

the_fizicx99 · Answer

It's already solved?

shamil98 · Answer

yes, x = -5

anonymous · Answer

Well they want me to use 2 methods. I already used one, which is the Substitution.

the_fizicx99 · Answer

@shamil98 do you want to do it? or meh?

shamil98 · Answer

I already gave you the equation for elimination, just solve it..

shamil98 · Answer

3x - 9y = 3
-3x +3/2y = 12

have fun

anonymous · Answer

Do I gotta combine them, correct?

anonymous · Answer

So*

shamil98 · Answer

yes..

the_fizicx99 · Answer

Using the substitution method?

anonymous · Answer

Elimination

the_fizicx99 · Answer

You asked which is the substitution.. ?

anonymous · Answer

No no, I already solved the substitution method. That's the one Shamil helped me with. They want me to use two methods. So I was asking, if for the elimination, that I have to combine the two equations.

the_fizicx99 · Answer

For elimination you eliminate either the y or x and combine the two equation

anonymous · Answer

So if I were to eliminate y, I would eliminate them from both equations?

shamil98 · Answer

fizi, hold on

the_fizicx99 · Answer

Yes, and combine the x and the .... kk

shamil98 · Answer

ellie, please read this http://www.purplemath.com/modules/systlin5.htm and then after you are enlightened work out the problem here so we can confirm it..