How do you solve $1.8 x + 3 y = 3$ $1.8x+3y=3$ and $- 2 x - 2.5 y = - 5$ $-2x-2.5y=-5$ ?

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Answer 1 · 2018-06-21T16:44:47

$x = 5, y = - 2$ $x=5,y=-2$

Fro the second equation we get

$- 2 x = - 5 + \frac{5}{2} y$ $-2x=-5+5/2y$
$x = \frac{5}{2} - \frac{5}{4} y$ $x=5/2-5/4y$
plugging this in the first equation we get

$\frac{9}{5} (\frac{5}{2} - \frac{5}{4} y) + 3 y = 3$ $9/5(5/2-5/4y)+3y=3$
$\frac{9}{2} - \frac{9}{4} y + 3 y = 3$ $9/2-9/4y+3y=3$
from here we get

$y = - 2$ $y=-2$
so
$x = 5$ $x=5$

How do you solve 1.8x+3y=31.8x+3y=31.8x+3y=3 and -2x-2.5y=-5−2x−2.5y=−5-2x-2.5y=-5?