Verified answer

{x + 2y=7

{-3x +5y=-10

Adição...

-2x+7y=-3

-2x=-3-7y

x=-3-7y/-2

x=3+7y/2

x+2y=7

3+7y/2+2y=7

3+7y+4y/2=14/2

11y=14-3

11y=11

y=11/11

y=1

x+2y=7

x+2.1=7

x=7-2

x=5

S={5, 1}

x + 2y = 7

-3x + 5y = -10

3x + 6y = 21

11y = 11

y = 1

x + 2 = 7

x = 5

pronto