Question

X+Y=30
X-Y=8

Resolva o sistema

Answer 1

X + Y = 30
X - Y = 8 +
‾‾‾‾‾‾‾‾‾‾‾‾
2X = 38
X = 38/2
X = 19

X - Y = 8
Y = X - 8
Y = 19 - 8
Y = 11

S = {19,11}

Answer 2

[método da adição]
X + Y = 30
X - Y = 8

2x = 38
x = 38/2
x = 19

x + y = 30
19 + y = 30
y = 30 - 19
y = 11