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13x - 5y = 10 3x - 2y = 14

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schooledmom | Salutatorian

Posted August 18, 2013 at 6:09 PM via web

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13x - 5y = 10

3x - 2y = 14

Tagged with algebra 1, math

2 Answers | Add Yours

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embizze | High School Teacher | (Level 1) Educator Emeritus

Posted August 18, 2013 at 6:18 PM (Answer #1)

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Solve the simultaneous equations 13x-5y=10; 3x-2y=14:

We can use linear combinations (multiplication/addition method);

13x-5y=10
3x-2y=14       Multiply eq1 by -2 and eq2 by 5

-26x+10y=-20
15x-10y=70   Add the two equations:

-11x+0y=50

`x=-50/11`

Substitute this into one of the original equations:

`3(-50/11)-2y=14`

`-2y=304/11`

`y=-152/11`

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The solution is `(-50/11,-152/11)`

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Check: `13(-50/11)-5(-152/11)=-650/11+760/11=110/11=10`

`3(-50/11)-2(-152/11)=-150/11+304/11=154/11=14`

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llltkl | College Teacher | Valedictorian

Posted September 1, 2013 at 5:51 PM (Answer #1)

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`13x - 5y = 10` --- (i)

`3x - 2y = 14`   ---- (ii)

These equations have to be solved.

Solution of the system of equations through elimination of y requires the following operation:

(i)*2-(ii)*5

------------------------

`26x - 10y = 20`

`15x - 10y = 70`

(-)-------------------------- 

`11x=-50`

`x=-50/11`

Put this value of x in eq.(i) to get,

`13*-50/11-2y=10`

`rArr 2y=(-650/11-10)=-760/11`

`rArr y=-380/11`

Therefore, the solution of the above equations is:

`x=-50/11`

`y=-380/11`

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