Question

resolva os seguintes sistemas, pelo método que preferir x+y=11 x-y=3

Answer 1

x + y = 11
x - y = 3

2x = 14
x = 7

x + y = 11
x = 11 - y
x = 11 - 7
x = 4

S = { 4 ; 7 }

Answer 2

x + y = 11
x -  y = 3

$x + y =11\\x=11-y$
--------------------------------
$x-y=3\\(11-y)-y=3\\11-2y=3\\-2y=3-11\\-2y=-8\\y= \frac{-8}{-2} \\y=4$
--------------------------------
$y=4\\\\x=11-y\\x=11-4\\x=7$
-----------------------------------
X = 7 e Y = 4