Question

rezlvati sistemul
x + 2y = 7
3x - 2y=3
(clasa a 9)

Answer 1

{x+2y = 7
{3x-2y = 3 
---------------(adunam)

=> x + 3x + 2y - 2y = 7 + 3 => 4x = 10 => x = 10/4 => x = 5/2

5/2+2y = 7 => 5+4y = 14 => 4y = 14-5 => 4y = 9 => y = 9/4

Answer 2

x + 2y = 7
3x - 2y=3
4x = 10 
x = 10 : 4 
x = 2,5 

2,5 + 2y = 7 
2y = 7 - 2,5 
2y = 4,5 
y = 4,5 : 2 
y = 2,25