Question

metodo da adiçao. 2x-2y=12. x+2y=11

Answer 1

2x - 2y=12
x + 2y =11

3x = 23
x = 23/3

x + 2y = 11
23 + 2y = 11
2y = 11 - 23/3
6y = 33 - 23
(6y = 10) : 2
3y = 5
y = 5/3

Answer 2

2x-2y=12
x+2y=11
cancela os 2y
ai soma e resolve assim:
3x=23
x=23/3

x+2y=11
23/3+2y=11
2y=11-23/3 
2y.3=11.3-23/3.3
6y=33-23
y=10/6
simplifica 
y=5/3