SOLUTION: 2x + 6y + 3z = −16 5x − 3y − 5z = 71 4x + 3y + 2z = 10 This is my first question! Find, x,y,z. Make sure they are all true!! x + y + z = 4 x − y + z = 2 x − y â

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Question 1151844: 2x + 6y + 3z = −16
5x − 3y − 5z = 71
4x + 3y + 2z = 10
This is my first question! Find, x,y,z. Make sure they are all true!!

x + y + z = 4
x − y + z = 2
x − y − 2z = −1
This is my second question! Find, x,y,z. make sure they are all true!
Thank you to whoever answers this!
Answer by Alan3354(69443)   (Show Source): You can put this solution on YOUR website!
2x + 6y + 3z = −16
5x − 3y − 5z = 71
4x + 3y + 2z = 10
This is my first question! Find, x,y,z.
======================
I'll do this one. You then try the others and email via the TY note for help or to check your work.
-------
I'll use elimination.
Multiply the 2nd & 3rd eqns by 2 so all the y coefficients are the same.
----
2x +  6y +  3z = −16
10x − 6y − 10z = 142
 8x + 6y +  4z = 20
-----
2x +  6y +  3z = −16
10x − 6y − 10z = 142
-------------------------------------- Add
12x - 7z = 126
---
10x − 6y − 10z = 142
 8x + 6y +  4z = 20
------------------------------------- Add
18x - 6z = 162
Now there are 2 eqns in 2 variables, x & z
---
12x - 7z = 126 --- Eqn A
18x - 6z = 162 --- Eqn B
---
Multiply Eqn A by 1.5 to make the x coeff's the same:
18x - 10.5z = 189
18x - 6z = 162 --- Eqn B
------------------------------------------- Subtract
-4.5z = 27
-9z = 54
z = -6
===================================
12x - 7z = 126 --- Eqn A
Sub for z and find x:
12x - 7*-6 = 126
12x = 84
x = 7
=========================

Sub for x & z in any equation and find y.



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