Question 384151
x – 5y + 2z = 0
x + 4y – z = 12
2x – y + 3z = 10 
:
Look at the equations, see if we can find a multiplier for one of the equations
that will eliminate two variables at the same time
:
There is! Multiply the last equation by -1 and add all three equations
x – 5y + 2z = 0
x + 4y – z = 12
-2x +y -3z = -10
----------------------Addition eliminates x and y, find z
0 + 0 - 2z = 2
Multiply by -1
2z = -2
divide both sides by 2
z = -1; they only asked for 1 variable