Question

Qual dos pares é a soluçao do sistema (x+y=15 2x-y=12)

Answer 1

$\boxed{ \left \{ {{x+y=15} \atop {2x-y=12}} \right. } \\ \\ 3x=27 \\ \\ x= \frac{27}{3} \\ \\ \boxed{x=9} \\ \\ \\ x + y = 15 \\ \\ 9+y=15 \\ \\ y=15-9 \\ \\ \boxed{y=6} \\ \\ \\ \\ \\ \\ \boxed{ \left \{ {{x=9} \atop {y=6}} \right. }$

Answer 2

x + y = 15
2x - y = 12 (+)
----------------
3x = 27
x = 27/3
x = 9

x + y = 15
9 + y = 15
y = 15 - 9
y = 6

R.: x = 9 e y = 6