the two equations are

-2x -5y =21

9x -7y = -65

I have tried all methods and i keep getting different answers, could somebody help me?

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- Aug 23rd 2009, 10:36 PMfvaras89need help for simultaneous equation
the two equations are

-2x -5y =21

9x -7y = -65

I have tried all methods and i keep getting different answers, could somebody help me? - Aug 23rd 2009, 10:48 PMred_dog
$\displaystyle \left\{\begin{array}{ll}-2x-5y=21\\9x-7y=-65\end{array}\right.$

Multiply the first equation with 9 and the second with 2:

$\displaystyle \left\{\begin{array}{ll}-18x-45y=189\\18x-14y=-130\end{array}\right.$

Add the equations:

$\displaystyle -59y=59\Rightarrow y=-1$

Now plug y in any of the equations and find x.