Question

Please help.What is the solution to the system of equations?

x-3y-z=-9

-2x+y+2z=3

2x+y+3z=8

a.(1, 3, 1)
b.(1, –3, 1)
c.(–1, 3, 1)
d.(1, 3, –1)

Answer 1

Eliminate y from 2 and 3.

Answer 2

you need help ?

Answer 3

@texaschic101 Just go ahead.

Answer 4

you think I should just do it ?

Answer 5

We need your wisdom.

Answer 6

x - 3y - z = -9
-2x + y + 2z = 3 -->(3)
---------------
x - 3y - z = -9
-6x + 3y + 6z = 9 (result of multiplying by 3)
---------------add
-5x + 5z = 0

-2x + y + 2z = 3 -->(-1)
2x + y + 3z = 8
----------------
2x - y - 2z = -3 (result of multiplying by -1)
2x + y + 3z = 8
----------------add
4x + z = 5

-5x + 5z = 0
4x + z = 5 --->(-5)
-------------
-5x + 5z = 0
-20x - 5z = -25 (result of multiplying by -5)
--------------add
-25x = -25
x = 1

now sub 1 in for x
4x + z = 5
4(1) + z = 5
4 + z = 5
z = 5 - 4
z = 1

now sub known values into any of the original equations
x - 3y - z = 9
1 - 3y - 1 = 9
-3y = 9
y = -3

check...
x - 3y - z = 9
1 - 3(-3) - z = 9
1 +9 -1= 9
9 = 9 (correct)

x = 1, y = 3, z = 1 or (1,3,1)

Answer 7

@texaschic101 I admire your patience.

Answer 8

it took a while....I messed up....but I finally fixed it and got the answer

Answer 9

thank you both