Question

resolva os sistemas abaixo
{x+y=11}
{x-y=3}

Answer 1

corta o +y e substitui o x

x-y=3
11-y=3
11-3=y
y=8

x-y=3
x-8=3
x=3+8
x=11

Answer 2

{ x + y = 11

{x - y = 3

2x = 14

x = 14/2

x= 7

x + y = 11

7 + y = 11

y = 11 - 7

y= 4

S=( 7 , 4)