Question

3. Resolva o sistema abaixo
{ 2x+y=5
{ x+y=1
a) S = {(4,3)}
b) S = {( -4, -3)}
c) S = {(-4,3)}
d) S = {(4,-3)}
e) S = {(4,-4)}

com calculo pfv

Answer 1

{2x + y = 5
{x + y = 1
=> x = - y

2.(1 - y) + y = 5

2 - 2y + y = 5
- 2y + y = 5 - 2
-y = 3.(-1)
y = -3

x = 1 - y
x = 1 - (-3)
x = 1 + 3
x = 4

S = { 4,-3}