Răspunsuri

2014-10-20T08:27:35+03:00
X = stilou
y = pix

7x + 6y = 235
2x + 3y = 80    | ×(-2)
---
 7x + 6y = 235
-4x - 6y = -160 
──────────  adunam ecuatiile
 3x   /   =   75
  x = 75 : 3 = 25 Lei un stilou
---
2x + 3y = 80
2 * 25 + 3y = 80
3y = 80 - 50
3y = 30
y = 30 : 3 = 10 Lei un pix
 

2 3 2
2014-10-20T08:41:33+03:00
X=stilou
y=pix
7x+6y=235  sistem de doua ecuatii cu 2 necunoscute
2x+3y=80
amplificam cu -2
7x+6y=235
-4x-6x=-160
3x=75
x=25       1 stilou=25 lei
2x25+3p=80
50+3p=80
3p=80-50
3p=30
p=10    1 pix=10 lei