Question

resolva os sistemas x+2y=7 x-2y=3

Answer 1

x+2y = 7
x-2y = 3
------------
x=10

Answer 2

x + 2y = 7
x - 2y = 3

x = 2y + 3
(2y + 3) + 2y = 7
2y + 2y = 7 - 3
4y = 4
y = 4/4
y = 1
__________

x = 2•1 + 3
x = 2 + 3
x = 5
__________
Verificação

5 + 2•y = 7
5 + 2•1 = 7
5 + 2 = 7
7 = 7

5 - 2•1 = 3
5 - 2 = 3
3 = 3