Question 59853
4x+5y=-16
5x-6y=-20

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Multiply the first equation by 6 and the second equation by 5

6(4x+5y)=6*-16
6*4x+6*5y=-96
24x+30y=-96   -------(a)

Multiply the second equation by 5,

   5 (5x-6y) =5*20

 5*5x - 5 * 6y = -100

25x - 30y = -100  ------(b)

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Add equations (a) and (b)

===> 24x - 30y + 25x + 30y = -96 + - 100

===> 24x + 25y + -30y + 30y = -196

===> 49x = -196

Divide on both sides by 49

===> x = -196/49 = -4

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Now substitute the value x=-4 in any one of the given pair of equations.

==>  4 * -4 + 5y = -16
==> -16 + 5y = -16
Add 16 on both sides

==> 5y = 0

Divide both sides by 5

==> y=0
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So the solution for the given pair of equations is,x=-4 and x=0.

Bye