## Help with Solution by Elimination

Quadratic equations and inequalities, variation equations, function notation, systems of equations, etc.
bellerum23
Posts: 16
Joined: Thu Oct 24, 2013 5:13 pm
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### Help with Solution by Elimination

Solve each system by addition, if possible

Having trouble understanding this.

x + y = 1
x - y = 7

Do I add it together like this:

x + y = 1
x - y = 7
--------------
2x = 8

Then, should I divide it like this:

8/2x = 4

My professor at the college went too fast for me to understand how to do Solution by Eliminations.

FWT
Posts: 153
Joined: Sat Feb 28, 2009 8:53 pm

### Re: Help with Solution by Elimination

Solve each system by addition, if possible

Having trouble understanding this.

My professor at the college went too fast for me to understand how to do Solution by Eliminations.
Your steps look fine to me. You can check by plugging your answer back into the system and making sure it works in both eqns. You can learn how to do it here.

Marvin Kalngan
Posts: 1
Joined: Sun Dec 15, 2013 3:04 am
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### Re: Help with Solution by Elimination

x + y = 1
x - y = 7
--------------
2x = 8 >>>>> y was eliminated

Then, divide both sides of the equation by 2 to solve for x

2x/2 = 8/2
x = 4

substitute the value of x in any of the two equations to solve for y

x + y = 1
4 + y = 1
y = 1 - 4
y = -3

x - y = 7
4 - y = 7
4 - 7 = y
-3 = y

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