## mariannu 2 years ago Solve the linear system using elimination. Hello you guys. I just want to know how you flip it. 2x - y= -11 y = -2x -13

1. Mertsj

rewrite the second equation by adding 2x to both sides.

2. chrismoon

for the second equation \[y=-2x-13\] you already solved for y. plug that y into the first equation, giving you\[2x-(-2x-13)=-11\]

3. mariannu

Don't get it.

4. mariannu

:p

5. Mertsj

So chrismoon, you are instructing the asker to ignore the directions which say to solve using elimination?????

6. mariannu

ALl I just want to know is just how to flip it. and thats it.

7. Mertsj

@mariannu Do what I said and then add the two equations to eliminate y from the system

8. Mertsj

What do you mean by flip it?

9. mariannu

So its y + 2x = -11???

10. Mertsj

|dw:1361938190124:dw|

11. mariannu

Ok that makes more sense thank you! ^.^ for the help. So I just do that for other equations like that right?

12. Mertsj

Do you mean other systems?

13. Mertsj

If so, the answer is yes.

14. mariannu

Ok, thank you much!!! ^.^ lol

15. Mertsj

yw

16. chrismoon

You're given two things: Equation 1)\[2x-y=-11\]Equation 2) \[y=-2x-13\] Equation 2 tells you what y is already. You can put what y equals (-2x-13 in this case) into the first equation for y. Equation 1 goes from \[2x-y=-11\] to \[2x-(-2x-13)=-11\] since\[y=-2x-13\] Simplify your Equation 1 from \[2x-(-2x-13)=-11\] to \[2x+2x+13=-11\]giving you \[4x=-24\] divide both sides by 4 to solve for x \[x=-6\] Now that you have solved for x, go all the way back to the original Equation 2\[y=-2x-13\] Since we know what x is now, plug it in\[y=-2(-6)-13\]giving us \[y=-1\] There you have it: \[y=-1\]and \[x=-6\]

17. Mertsj

@chrismoon Why do you keep telling the asker to ignore the directions given?

18. chrismoon

Sorry, didn't see you guys already talked about it before I posted. Didn't get notified you guys got it taken care of.

19. Mertsj

@chrismoon The problem says to solve by elimination. You keep telling the asker to use substitution.

20. chrismoon