2.) Solve the system of equations:

x - y - z = 0

2x + 3y + z = 17

z + 2y = 7

GAMEMASTERX40 Feb 10, 2019

#1**+2 **

x - y - z = 0

2x + 3y + z = 17

z + 2y = 7

No set way to do this GM.....but here is an approach....the idea is to get to two equations and two unknowns

Using the 3rd equation.....we can write z = 7 - 2y

Sub this into the first two equations for z

x - y - [ 7 - 2y ] = 0 ⇒ x - y - 7 + 2y = 0 ⇒ x + y = 7 (4)

2x + 3y + [ 7 - 2y ] = 17 ⇒ 2x + y + 7 = 17 ⇒ 2x + y = 10 (5)

We can rewrite (4) as y = 7 - x

Sub this into (5)

2x + ( 7 - x) = 0

x + 7 = 10

x = 3

So...y = 7 - x = 7 - 3 = 4

And

z = 7 - 2(y) = 7 - 2(4) = - 1

So { x, y, z } = { 3, 4 , -1 }

CPhill Feb 10, 2019