Question

Resolva cada sistema : 2x+y=10 e x+y=6

Answer 1

2x-y=6 (x3)

x+3y=10

6x-3y=18

x+3y=10    + (cancela -3x com 3x)

___________

7x = 28

x=4

Substituindo o x:

2eq) x+3y=10

       4+3y=10

         3y=6

             y=2

x=4, y=2

Answer 2

2x+y=10

x+y=6 (-1)

2x + y = 10

- x - y = -6 (+)

----------------------

x = 4

x + y = 6

4 + y = 6

y = 6 - 4

y = 2

R : x = 4; y = 2