How do you solve using gaussian elimination or gauss-jordan elimination, $3 x - 4 y = 18$ $3x-4y=18$ , $8 x + 5 y = 1$ $8x+5y=1$ ?

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Answer 1 · 2018-01-18T14:48:50

$x = 2$ $x=2$ and $y = - 3$ $y=-3$

From first equation, $y = \frac{3 x - 18}{4}$ $y=(3x-18)/4$

After plugging value of $y$ $y$ into second equation,

$8 x + 5 \cdot \frac{3 x - 18}{4} = 1$ $8x+5*(3x-18)/4=1$

$\frac{32 x + 15 x - 90}{4} = 1$ $(32x+15x-90)/4=1$

$\frac{47 x - 90}{4} = 1$ $(47x-90)/4=1$

$47 x - 90 = 4$ $47x-90=4$

$47 x = 94$ $47x=94$ , so $x = 2$ $x=2$

Thus, $y = \frac{3 \cdot 2 - 18}{4} = - 3$ $y=(3*2-18)/4=-3$

How do you solve using gaussian elimination or gauss-jordan elimination, 3x−4y=183x-4y=18, 8x+5y=18x+5y=1?