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2x - 5y = 4 3x + 4y = 9

solve the system using any algebraic method
asked Nov 17, 2011 in Algebra 2 Answers by anonymous

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1 Answer

1) 2x - 5y = 4

2) 3x + 4y = 9

multiply eq(1) by 3 and eq(2) by -2, add:

 6x  -  15y  =  12

-6x  -   8y   = -18


         - 23y  =  -6

y = 6/23

using eq(1):

2x - 5(6/23) = 4

2x - 30/23 = 4

2x = 4 + 30/23 = 92/23 + 30/23 = 122/23

x = 61/23

check using eq(2):

3(61/23) + 4(6/23) = 9

183/23 + 24/23 = 9

9 = 9

x = 61/23, y = 6/23
answered Nov 17, 2011 by Battleaxe Level 6 User (23,120 points)

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