Question

how to solve linear equation with three variables

x + y + z = -5
-2x - y + z = -1
x - 2y - z= 0

Answer 1

easy get rid of your Z variables first
add 1st equation to your 3rd equation
then add 2nd equation to your 3rd equation
this way you have 2 equations with x and y
solve them like you would a regular x and y system
Once you know x or y sub it into 2 of your equations, maybe 2nd and 3rd and solve for the remaining variables.

Answer 2

you could do a matrix on your calculator too :)

Answer 3

I just tried to explain this to someone and it took me like half an hour haha. I highly recommend watching this video.

http://www.youtube.com/watch?v=woqq3Sls1d8

your options are 1)substitution 2)subtraction/elimination 3)row reducing an augmented matrix. I guess method 2 and 3 are the same thing.

for a small system of equations I would use method 1, for a large one I could use method 3.

Answer 4

yes the matrix feature on the TI84 or TI83 is real easy to use