Question

Solve:
x + 2y + z = 7
3x - y + z = - 12
4x + 3y - 2z = 9

Answer 1

Substitution games! :-D

I would personally start with rewriting the middle one as y = 3x+z+12

Second, rewrite the first in terms of z like so: z=x+2y-7

Plug this "z" polynomial in the y=2x+z+12 and simplify

And so starts the pattern ;-)

Can you write the results of these steps so far?

Answer 2

Technique:

1. Write everything from an equation in terms of one variable from that polynomial equation.
2. Make a substitution
3. Simplify

Rinse & repeat

Answer 3

Eventually you'll break it down to x = some #, y = some #, or z = some # depending on how you choose to substitution. Once you have that, you can go back and plug & chug into other equations. Two variables and two equations is fast to do, 3 variables and 3 equations is quick of bit of time for me to show one possible way (out of many other correct ways) to do all the steps...

Answer 4

Well so far I have x = 0 , so I should be able to go from here. Thanks!

Answer 5

You're welcome @LinuxCharmd :-) (PS: Is that in the OS kernel, Linux?)