Question

resolva os sistemas {2x- y=7
{ x-y=6

Answer 1

Bom Dia!

$\left\{\begin{matrix}2x-y=7\\x-y=6\\\end{matrix}\right.$

$\left\{\begin{matrix}2x-y=7(-1)\\x-y=6\\\end{matrix}\right.$

$\left\{\begin{matrix}-2x+y=-7\\x-y=6\\\end{matrix}\right.$

Pelo método da adição;

-2x+x+y-y=-7+6

-x=-1 (-1)

x=1

_____________

$\boxed{x-y=6}$

1-y=6

-y=6-1

-y=5 (-1)

y=-5

_____________

Att;Guilherme Lima

Answer 2

{2x - y = 7  (i)

{x - y = 6    (ii)

Adição ;

{2x - y = 7  

{x - y = 6    .( - 2)

2x - y = 7

-2x + 2y = - 12

y = - 5

{x - y = 6    (ii)

x - ( -5) = 6

x + 5 = 6

x = 6 - 5

x = 1

s={ - 5 , 1 }