Elimination Method

MR. BIGSBY'S MATH WORLD

Elimination Method

12/10/2015

24 Comments

Combine equations to eliminate one variable.

24 Comments

Victoria

12/10/2015 12:50:07 pm

This makes everything so mush easier to understand

Cora C.

12/14/2015 04:03:21 pm

I agree!

Scott

12/10/2015 01:28:22 pm

Hi cool video.

Mia

12/10/2015 01:57:02 pm

Hello, nice video.

Angie L.

12/10/2015 02:38:15 pm

Hello, I was a little confused in class, but after watching the video, I understand the skill more better now! Great Video!

Emmett

12/10/2015 02:53:12 pm

What about an equation like this one, and is it possible?
2x+2y=3x
-2x+2y=5

Mr. Bigsby

12/10/2015 06:57:06 pm

Nice challenge problem!
Just like when we are solving, I am going to combine those like terms on the first equation before I do anything else.
2x + 2y = 3x
-3x -3x
-1x + 2y = 0

Now I have a system like in class
-1x + 2y = 0
-2x + 2y = 5

This needs a little manipulating to allow elimination. I'm going to multiply the bottom equation by -1. This will just change all the signs.

-1x + 2y = 0
2x + -2y = -5

Now I am ready to combine and eliminate!
1x = -5
or
x = -5

Substitute that x = -5 back into the original equation and solve for y.
2(-5) + 2y = 3(-5)
-10 + 2y = -15
+10 +10
2y = -5
/2 /2
y = -2.5

Solution (-5, -2.5)

Josie

12/10/2015 06:03:05 pm

I was confused in class but this video helped to make it clear

Krista

12/11/2015 03:31:24 am

This video helped a lot.

Tapasya

12/11/2015 11:08:57 am

oops. I'm late. This video should have helped if I did my homework on time

Avery

12/11/2015 12:30:17 pm

Cool

Victoria

12/11/2015 06:37:16 pm

Is it possible to have a problem where you will have to solve 3 equations?

Kate

12/12/2015 01:17:22 am

Oh. So if we can't solve it we just need to manipulate I find this very easy now.

Autumn

12/12/2015 12:09:13 pm

I was absent the day that we learned this so I watched the video and it helped me.

Jordan Christian

12/13/2015 06:19:45 am

Ray Sutton

12/13/2015 02:30:55 pm

Hi good video

Blake Jacobs

12/14/2015 11:08:11 am

Hi good video it helped when I was trying to figure it out with my parents

Sean

12/14/2015 07:37:17 pm

Hey

Scott Talley

12/15/2015 05:46:03 pm

Hi.

jacob

12/16/2015 05:20:44 am

Nataliw

12/17/2015 12:08:56 pm

Jaden

12/18/2015 05:40:19 am

Done

Brendan Gavin

12/21/2015 04:47:34 pm

Gino

1/5/2016 01:04:59 pm

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Elimination Method

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