SOLUTION: I am not good at these types of problems and I dont have a calculator to calculate these types of problems any help would be great. I am not even sure if I put these under the cor

Algebra ->  Matrices-and-determiminant -> SOLUTION: I am not good at these types of problems and I dont have a calculator to calculate these types of problems any help would be great. I am not even sure if I put these under the cor      Log On


   



Question 298233: I am not good at these types of problems and I dont have a calculator to calculate these types of problems any help would be great. I am not even sure if I put these under the correct type of problem

Solve any way you can
3x - y - 2z = 11
x – 2y + 3z = 12
x + y - 2z = 5

John

Answer by amoati(11) About Me  (Show Source):
You can put this solution on YOUR website!
3x - y - 2z = 11 -- (1)
x – 2y + 3z = 12 -- (2)
x + y - 2z = 5 -- (3)
multiplying (3) by 2 yields 2x + 2y - 4z = 10 then adding this to 2 yields:
3x - z = 22 -- (4)
Then multiplying (1) by 2 yields 6x -2y - 4z = 22 then subtracting it from (2) yields:
5x - 7z = 10 -- (5)
multiplying (4) by 7 yields 21x -7z = 154 and then subtracting it from (5) yields:
16x = 144 --> x = 9 using this in (4), z = 5, using these values in (3), y = 6
So x = 9, y = 6, z = 5