how to solve 4X-5y=11,7x+9y=3 USING ELIMINATION
asked Apr 19 in Geometry Answers by bi

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1 Answer

how to solve 4X-5y=11,7x+9y=3 USING ELIMINATION

The eqns are:

4x - 5y = 11

7x + 9y = 3

Let's eliminate the y's say, by multiplying the 1st eqn by 9 and the 2nd eqn by 5.

This gives us,

36x - 45y = 99

35x + 45y = 15

Now simply add the two eqns together, to give

71x = 114

x = 114/71

Substituting for x = 114/71 in the 1st eqn, we get

4(114/71) - 5y = 11

456/71 - 11*(71/71) = 5y

456 - 781 = 71*5y

-325 = 71*5y

-65 = 71y

y = -65/71

Answers: x = 114/71, y = -65/71

answered Apr 20 by Fermat Level 11 User (75,720 points)

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