Quote:
Originally Posted by Never Win
(#1): 2x+y-z=2
(#2): x+3y+2z=1
(#3): x+y+z=2
Solution: Begin by eliminating the term with x, this time from equations 2 and 3 as follows.
(#1): 2x +y -z = 2
-2*(#2): -2x-6y-4z=-2
(#1) - 2*(#2): -5y-5z = 0
(#1) - 2*(#3): -y -3z= -2
You're allowed to create new equations by
1) multiplying an old equation by a constant.
Idea: If Left Side = Right Side, then certainly
c*(Left Side) = c*(Right Side)
2) Adding two equations together (on both sides)
Idea: If A = B and C = D, then
A + C = B + D
So combining those ideas together, we can multiply an equation by a constant and add the resulting equation to an existing one. In the case above, we used this technique to cancel the x's in eqns #1 and #2.
Hope this helps.
-BW