Question

Use elimination to solve the system of equations.
x+2y+3z=9
x+3y+2z=5
x+4y-z=-5

Answer 1

Know what elimination means?

Answer 2

here is an example:

a + 2b = 5
-a + b = 1

If I add these, a gets eliminated:

a + (-a) + 2b + (b) = 5 + (1)
0a +3b = 6
3b = 6
3b/3 = 6/3
b=2

Then you can can substitute that into either one to find a, but the elimination part allowed me to find b.

A similar thing can be done to turn 3 equations in 3 unknowns into 2 in 2 unknowns, then those into 1 with 1 unknowns.