Solving Systems of Equations by Elimination
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Solving Systems of Equations by Elimination
3) x − y = 11
2x + y = 19
6) 8x + y = −16
−3x + y = −5
10) −4x + 9y = 9
x − 3y = −6
12) −7x + y = −19
−2x + 3y = −19
2x + y = 19
6) 8x + y = −16
−3x + y = −5
10) −4x + 9y = 9
x − 3y = −6
12) −7x + y = −19
−2x + 3y = −19
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Re: Solving Systems of Equations by Elimination
Using elimination you simply subtract the bottom equation from the top.
3) xy=11
2x+y=19
For that problem you would do
xy=11
(2x+y=19)
x2y=8
I put the original part in parenthesis to show that it's not 2x, but everything is subtracted from the xy=11.
How I got my answer:
x2x=x, yy=2y, 1119=8.
6) 8x+y=16
3x+y=5
8x+y=16
(3x+y=5)
11x=11
x=1
How I Got My Answer:
8x(3x)=11x. yy=0, so y is cancelled out of the equation. 16(5)=11. 11x=11. Divide both sides of the equation by 11 and you get x=1.
Try the last two on your own.
10) 4x+9y=9
x3y=6
4x+9y=9
(x3y=6)
12) 7x+y=19
2x+3y=19
7x+y=19
(2x+3y=19)
3) xy=11
2x+y=19
For that problem you would do
xy=11
(2x+y=19)
x2y=8
I put the original part in parenthesis to show that it's not 2x, but everything is subtracted from the xy=11.
How I got my answer:
x2x=x, yy=2y, 1119=8.
6) 8x+y=16
3x+y=5
8x+y=16
(3x+y=5)
11x=11
x=1
How I Got My Answer:
8x(3x)=11x. yy=0, so y is cancelled out of the equation. 16(5)=11. 11x=11. Divide both sides of the equation by 11 and you get x=1.
Try the last two on your own.
10) 4x+9y=9
x3y=6
4x+9y=9
(x3y=6)
 Spoiler:
 5x+12y=15
12) 7x+y=19
2x+3y=19
7x+y=19
(2x+3y=19)
 Spoiler:
 5x2y=0
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ThatAwkwardKid Admin
 Posts : 649
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Re: Solving Systems of Equations by Elimination
What are you confused about? Sorry, I was trying to make it less complicated :P
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I love Bailey, Rise, Rawr (and her twin whose hair flips the wrong way), and Starr. They are my best friends ever. But I love Bailey the most because nobody can compare to her.
ThatAwkwardKid Admin
 Posts : 649
Join date : 20110310
Age : 21
Location : Insideout
Re: Solving Systems of Equations by Elimination
If you don't mind my helping. I see the problem... This is rather easy math here... I'll take 6 there as an example.
6) 8x + y = −16
−3x + y = −5
So you want to arrange it as a subtraction equation as Guard did right? So it would be:
3x+y=5
(8x+y=16)
________
You'll notice that subtracting the bottom y with the top y gets rid of them. The leaves you with:
11x=11 which means
x=1
Then you take what you get for x and put it into the original equations, for example, putting it back into the first equation would look like:
8x + y = −16
8(1)+y=16
8+y=16
y=16+8
y=8
Though to be honest... it has been some... 4 or 5 years since I've had to do this math... So I'm not sure... But you should try subbing the x value that I found into the other equation... You should get the same thing I got for the one that I just tried above. You should get y=8, I checked it, but you try it.
6) 8x + y = −16
−3x + y = −5
So you want to arrange it as a subtraction equation as Guard did right? So it would be:
3x+y=5
(8x+y=16)
________
You'll notice that subtracting the bottom y with the top y gets rid of them. The leaves you with:
11x=11 which means
x=1
Then you take what you get for x and put it into the original equations, for example, putting it back into the first equation would look like:
8x + y = −16
8(1)+y=16
8+y=16
y=16+8
y=8
Though to be honest... it has been some... 4 or 5 years since I've had to do this math... So I'm not sure... But you should try subbing the x value that I found into the other equation... You should get the same thing I got for the one that I just tried above. You should get y=8, I checked it, but you try it.
Last edited by JENOVA's SOLDIER on Sat Feb 04, 2012 10:32 pm; edited 1 time in total
JENOVA's SOLDIER Beginner
 Posts : 96
Join date : 20120126
Age : 24
Location : Canada
Re: Solving Systems of Equations by Elimination
I'm not even this far into math yet. So I have no clue. Lol
WolvesRule1 Admin
 Posts : 4289
Join date : 20110726
Age : 20
Location : Small town USA. Population 477
Re: Solving Systems of Equations by Elimination
I was right except for my last bit of math. Sorry, I'll go fix it.
Edit: There all better. I messed up the signs and screwed myself up lol. It happens to everyone
Edit: There all better. I messed up the signs and screwed myself up lol. It happens to everyone
JENOVA's SOLDIER Beginner
 Posts : 96
Join date : 20120126
Age : 24
Location : Canada
Re: Solving Systems of Equations by Elimination
what do with fraction like if x or y your fraction
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