Solve the system by substitution. 2x – y + z = -4
z = 5

-2x + 3y - z = -10
(-8.7.5)
(-8.-7.5)
(8.–7.5)
(-8, -7 -5)

{x,y,z} = {-8,-7,5}

Step-by-step explanation:

/ Solve equation [2] for the variable  z  

  [2]    z = 5  

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

  [1]    2x - y + (5) = -4

  [1]    2x - y = -9

// Plug this in for variable  z  in equation [3]

  [3]    -2x + 3y - (5) = -10

  [3]    -2x + 3y = -5

// Solve equation [1] for the variable  y  

 [1]    y = 2x + 9  

// Plug this in for variable  y  in equation [3]  

  [3]    -2x + 3•(2x+9) = -5

  [3]    4x = -32

// Solve equation [3] for the variable  x  

  [3]    4x = - 32  

  [3]    x = - 8  

// By now we know this much :

x = -8

   y = 2x+9

   z = 5

// Use the  x  value to solve for  y  

 y = 2(-8)+9 = -7  

Solution :

{x,y,z} = {-8,-7,5}

answer: l

step-by-step explanation: