Resposta :
Resposta:
{x+y=17
{x-y=3
-----
x=3+y
______
x+y = 17
3+y+y=17
3+2y=17
2y=17-3
2y=14
y=14÷2
y=7
_____
x=3+y
x=3+7
x=10
y=7
a)10
Resposta:
{x+y=17
{x-y=3
-----
x=3+y
______
x+y = 17
3+y+y=17
3+2y=17
2y=17-3
2y=14
y=14÷2
y=7
_____
x=3+y
x=3+7
x=10
y=7
a)10