Question

Resolva:

A) x+y=12
x-y= 2
_________

Answer 1

x=12-y ........12-y-y=2
x=12-5 -........2y=-12+2(*1)
x=7 ........y=10
.............y=2/10
.............y=5

Answer 2

{x + y = 12

{x - y = 2

2x = 14

x= 14/2

x= 7

x + y = 12

7 + y = 12

y = 12 - 7

y = 5

S= ( 7 , 5)