Question

if 2y+z=17,2z+x=15,2x+y=10then x+y+z=​

Answer 1

Answer:

Solve equation [3] for the variable  y 

 

[3] y = -2x + 10

// Plug this in for variable  y  in equation [1]

  [1] 2•(-2?+10) + z = 17   [1] z = -3

// Solve equation [2] for the variable  x 

 

[2] x = -2z + 15

// Plug this in for variable  x  in equation [1]

  [1] z = -3   [1] 9z = 57

// Solve equation [1] for the variable  z 

  [1] 9z = 57    [1] z = 19/3 

// By now we know this much :

  y = -2x+10   z = 19/3   x = -2z+15

// Use the  z  value to solve for  x 

  x = -2(19/3)+15 = 7/3 

// Use the  x  value to solve for  y 

  y = -2(7/3)+10 = 16/3 

Solution :

 {y,z,x} = {16/3,19/3,7/3}