Question

sitemul x-3y=16 si 3x-y=12 repede va rog

Answer 1

 x-3y=16
-9x+3y=-36
(Am inmultit a doua eculatie cu -3.)

Folosim metoda reducerii si avem:

-8x=-20
$x= \frac{20}{8} = \frac{5}{2}$

x-3y=16 ⇒ -3y=16-x ⇒ y=(16-x)/(-3)

$y= \frac{16-2,5}{-3} = \frac{13,5}{-3} =-4,5= \frac{-9}{2}$