SOLUTION: Solve the following system algebraically: 3x + 5y – z = 2; -x – 8y + 3z = -6; 3z = 2x.

Algebra ->  Systems-of-equations -> SOLUTION: Solve the following system algebraically: 3x + 5y – z = 2; -x – 8y + 3z = -6; 3z = 2x.      Log On


   

Question 633363: Solve the following system algebraically: 3x + 5y – z = 2; -x – 8y + 3z = -6; 3z = 2x.
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi,

 3x + 5y – z = 2 

-x – 8y + 3z = -6  |multipling 1st EQ by 8, 2nd by 5 and adding EQs to eliminate y

 24x - 8z = 16

-5x  +15z = -30

  19x + 7z = -14

    z = 2/3x

  19x + 14/3x = -14  ||Multiplying thru by 3 so as all denominators = 1

71x = -42

         x = -42/71 , z = -28/71  

substitute x and z into 1st EQ to find y = %282+%2B+98%2F71%29%2F5+=+%28240%2F71%29%2F5+=+48%2F71