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December 18, 2014

December 18, 2014

Posted by **Mathew** on Thursday, January 13, 2011 at 8:17pm.

7x - 2y =3

2x +y = 4

?????????????????

- MATHH -
**helper**, Thursday, January 13, 2011 at 9:30pm(1) 7x - 2y =3

(2) 2x + y = 4

look to see which variable is easier to get rid of. since the first equation has -2y, multiple the 2nd equation by 2, so that you get 2y. -2y + 2y = 0, so you will have eliminated the y variable

Multiple (2) by 2

2 (2x + y = 4) = 4x + 2y = 8

Add the two equations together

7x - 2y = 3

4x + 2y = 8

11x + 0 = 11

11x = 11

x = 1

Substitute x = 1 in either equation (1) or (2) to find y.

7x - 2y = 3

7(1) - 2y = 3

7 - 2y = 3

2y = 4

y = 2

To check

substitute x = 1, y = 2

in the other equation (1)

2x + y = 4

2(1) + 2 = 4

2 + 2 = 4

4 = 4

so it's correct

- MATHH -
**Mathew**, Thursday, January 13, 2011 at 9:40pmThanks a lot:D

- MATHH -
**helper**, Thursday, January 13, 2011 at 9:52pmyou're welcome

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