Question

PFFR ME AJUDEM !!!!

{x+2y=4
{x-y=1

Answer 1

{x+2y =4        
{x-y=1      x=1+y

x+2y =4    
1+y+2y=4
3y=4-1
y=3/3
y=1
x-y=1
x-1=1
x=1+1
x=2
prova
2+2.1=4
2.2=4
4=4
2-1=1
1=1