SOLUTION: Solve x + y + z = 11 2x + y - z = 13 x = 2y

Algebra.Com
Question 65601This question is from textbook An Incremental Development
: Solve
x + y + z = 11
2x + y - z = 13
x = 2y
This question is from textbook An Incremental Development

Answer by praseenakos@yahoo.com(507)   (Show Source): You can put this solution on YOUR website!
QUESTION:

Solve
x + y + z = 11
2x + y - z = 13
x = 2y

ANSWER:
x + y + z = 11 -----------------------(1)

2x + y - z = 13 -----------------------(2)

x = 2y -------------------------------(3)



Fron (2) we have, x = 2y.



Substitute this value in (1) and (2)



==>
2y + y + z = 11



3y + z = 11 ------------------------(4)


2(2y) + y - z = 13


4y + y - z = 13



==> 5y - Z = 13 -------------------------(5)



Let's take (4) and (5) together,




3y + z = 11 ------------------------(4)



5y - Z = 13 ------------------------(5)

_____________________________________________________________________________

Add (4) and (5) ====>


3y + z + 5y - Z = 11 + 13



==> 8y = 24


Divide both sides by 8,



==> 8y/8 = 24/8



==> y = 3



Substitute the value of y in equation (3) x = 2y




==> x = 2* 3



==> x = 6




Input the values of x and y in equation (1)



6 + 3 + z = 11


==> 9 + z = 11



Subtract 9 from both sides,



==> 9 + z - 9 = 11 - 9



==> z = 2



so the solution is,



x = 6
y = 3
z = 2




Hope you understood.


Regards.

praseenakos@yahoo.co.in





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