x+2y-z= -3
2x-y+3z=14
x+4y-2z= -8
2007-10-02 16:06:22 · 7 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
3x + 6y - 3z = - 9
2x - y + 3z = 14-----ADD
5x + 5y = 5
-2x - 4y + 2z = 6
x + 4y - 2z = - 8----ADD
-x = - 2
x = 2
10 + 5y = 5
5y = - 5
y = - 1
2 - 2 - z = - 3
z = 3
x = 2 , y = - 1 , z = 3
2007-10-02 21:51:00 · answer #1 · answered by Como 7 · 1⤊ 0⤋
x + 2y - z = -3
2x - y + 3z = 14
Eliminate 1 of them first. Let's start with x.
2 (x + 2y - z) = 2 (-3)
2x + 4y - 2z = -6
Let's eliminate x.
2x + 4y - 2z = -6
2x -y + 3z = 14
---------------------- -
5y - 5z = -20
x + 2y - z = -3
x = -3 -2y + z
Let's put x in the last equation:
x + 4y - 2z = -8
(-3 -2y + z) + 4y - 2z = -8
-3 + 2y - z = -8
2y - z = -8 + 3
2y - z = -5
Let's eliminate z:
5y - 5z = -20
5 (2y - z) = 5 (-5)
5y - 5z = -20
10 y - 5z = -25
-------------------- +
15 y = -45
y = 3
Let's plug in y to 1 of the equations above:
5y - 5z = -20
15 - 5z = -20
- 5z = -20 - 15
5z = 35
z = 7
Let's plug in both to the 1st equation. Remember that y = 3 and z = 7.
x + 2y - z = -3
x + 6 - 7 = -3
x = -3 - 6 + 7
x = -2
Let's check with the other 2 equations:
2x - y + 3z = -4 -3 + 21 = 14 (Correct)
x + 4y - 2z = -2 + 12 - 14 = -8 (Correct)
2007-10-02 23:21:22 · answer #2 · answered by Steven Prasetya 2 · 0⤊ 1⤋
Concur:
2
-1
3
2007-10-02 23:18:43 · answer #3 · answered by fenx 5 · 0⤊ 0⤋
x = z - 2y - 3
2(z - 2y - 3) - y + 3z = 14
2z - 4y - 6 - y + 3z = 14
5z - 5y = 20
z - y = 4
(z - 2y - 3) + 4y - 2z = -8
2y - z = -5
z = 2y + 5
2y + 5 - y = 4
y = -1
z = 3
x = 3 - 2(-1) - 3 = 3 + 2 - 3 = 2
x = 2
y = -1
z = 3
2007-10-02 23:23:07 · answer #4 · answered by Jeremiah F 3 · 0⤊ 0⤋
x=-3-2y+z
-6-5y+5z=14
2y-3-z=-8
5z-5y=20, z-y=4, z=y+4
2y=z-5=y-1
z=3
y=-1
x=2
2007-10-02 23:14:50 · answer #5 · answered by おぁな 2 · 0⤊ 0⤋
y=0
z=5/2
x=-3
2007-10-02 23:26:22 · answer #6 · answered by starr 4 · 0⤊ 0⤋
use excel
2007-10-02 23:14:02 · answer #7 · answered by vlee1225 6 · 0⤊ 0⤋