👤

[tex] \left \{ {{ \frac{4}{x}- \frac{y}{3}= \frac{40}{3} } \atop { \frac{3}{x}+ \frac{y}{4}= \frac{30}{4} }} \right. [/tex]

mersi :)


Răspuns :

⇒{4/x=40/3+y/3
   {3/x=30/4-y/4

{4/x=(40+y)/3
{3/x=(30-y)/4

{12=x(40+y)
{12=x(30-y)

{40x+xy=12
{30x-xy=12
  ⇒40x+30x+xy-xy=12+12
70x=24
x=24/70=12/35
x=12/35
din 40x+xy=12⇒40·12/35+12y/35=12

480/35+12y/35=12
12y/35=12-480/35
12y/35=12-96/7
12y/35=(12·7-96)/7
12y/35=-12/7
y=(-12·35)/7·12
y=-5