Question

I need assistance fast please with System of Equations! Please

Answer 1

so which variable you want to eliminate first ?

Answer 2

Well that is what is confusing ._. My teacher just gave this to us without any explination I have only been doing 2 variables until now

Answer 3

O I just filled in the variables for x y and z for what was given and found it out that way

Answer 4

x + 2y + 3z = 9 --> (-1)
x + 3y + 2z = 5
-------------------
-x - 2y - 3z = -9 (result of multiplying by -1)
x + 3y + 2z = 5
-------------------add
y - z = -4

x + 3y + 2z = 5
x + 4y - z = -5 --->(-1)
------------------
x + 3y + 2z = 5
-x - 4y + z = 5 (result of multiplying by -1)
----------------add
-y + 3z = 10

y - z = -4
-y + 3z = 10
------------add
2z = 6
z = 3

now sub 3 in for z
y - z = -4
y - 3 = -4
y = -4 + 3
y = -1

now sub 3 in for z and -1 in for y
x + 2y + 3z = 9
x + 2(-1) + 3(3) = 9
x - 2 + 9 = 9
x + 7 = 9
x = 9 - 7
x = 2

now lets check our answers..
x + 4y - z = -5
2 + 4(-1) - 3 = -5
2 - 4 - 3 = -5
2 - 7 = -5
-5 = -5 (correct)

x = 2, y = -1, and z = 3

any questions ?