Question

Resolva usando os três métodos :

a) {x+y=7
{x-y=3

b){2x-2y=12
{x-2y=0

c){-x+y=5
{2x-y=2

Answer 1

a) {x+y=7
    {x-y=3
   2x=10
   x= 10/2
   x=5

b) {2x-2y=12
    {x-2y=2(-1)
{2x-2y=12
{-x+2y=-2
x=10

c) {-x+y=5
    {2x-y=2
  x=7