# Thread: How do you do system of equations?

1. ## How do you do system of equations?

Ok, i was just on a site for tutoring but it isn't making much sense to me!
What steps do i follow through when doing this?

y=3x+7
y=x-9

2. To solve it, set the two expressions equal to each other.

$3x+7 = x-9$

Then solve for x, to get:

$x=-8$

3. ok, so on one like

y=2x+3
y=3x+1

itll be 2x + 3=3x+1?

and solve from there? aren't you suppose to change signs when bringing it over?

4. Switch signs? Sort of, let me give you a step by step version of this:

$2x+3=3x+1$

Subtract 1 from both sides:

$2x+2=3x$

Subtract 2x from both sides:

$
2=1x$

So:

$x=2$

Do you see?

5. I think so.

So on one like

y=2x-10
y=4x-8

itll be 2x-10 = 4x-8

2x=-2

x=-1?

ha i suck at combining like terms and what not lol.

6. Yeah, it looks like you've got it now.

7. Yay! Thanks for your time! = ]

8. Originally Posted by topaz192
Ok, i was just on a site for tutoring but it isn't making much sense to me!
What steps do i follow through when doing this?

y=3x+7
y=x-9