Question

Qual é o valor de z no sistema:
x-2y+z=3
2x+y-4z=0
-x+3y-2z=-3
a) - 3
b) 0
c) 2
d) 3
e)4

Answer 1

{x-2y+z= 3. I eq
{2x+y-4z= 0 II eq
{-x +3y-2z= -3. III eq
--------------------
x-2y+z= 3
2x +y -4z= 0 x(2)
--------------------
x-2y+z= 3
4x +2y-8z= 0
----------------
5x-7z= 3

2x+y -4z=0x(-3)
-x +3y -2z=-3
-----------------
-6x -3y+12z =0
-x +3y -2z= -3
------------------
-7x +10z = -3

5x -7z = 3 x(7)
-7x +10z = -3 x(5)
-------------------
35x -49z = 21
-35x +50z= -15
------------------

z= 6





valor de x// 5x-7z=3 5x-7*6= 3 5x-42= 3 5x= 3+42 x= 45/5 x= 9// valor de y// x-2y+z= 3 9 -2y+6= 3 -2y= 3-6-9 -2y= 3-15 -2y= -12 y= -12/-2// y= 6