help? please?
-6x + 6y - 5z = -6
4x - 2y + 4z = 8
x + y - 6z = 5
thanks!
2007-04-27 20:17:07 · 6 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
-6x + 6y - 5z = -6 equation(1)
4x - 2y + 4z = 8 equation(2)
x + y - 6z = 5 equation(3)
multiply 2 to eqaution(3) then add to equation (2)
x + y - 6z = 5 (*2)
2x +2y - 12z = 10
(+)
4x - 2y + 4z = 8
-----------------------
6x - 8z =18
6x = 18 + 8z equation(4)
Replace equation(4) into equation(1)
-6x + 6y - 5z = -6 equation(1)
-(18 + 8z) + 6y -5z = -6
6y - 13z = 12
6x = 18 + 8z
6y - 13z = 12
Assume z = 0
:. x = 3 and y = 2
2007-04-27 20:34:45 · answer #1 · answered by Tubby 5 · 0⤊ 0⤋
-6x + 6y - 5z = -6 equation(1)
4x - 2y + 4z = 8 equation(2)
x + y - 6z = 5 equation(3)
multiply 2 to eqaution(3) then add to equation (2)
x + y - 6z = 5 (*2)
2x +2y - 12z = 10
(+)
4x - 2y + 4z = 8
-----------------------
6x - 8z =18
6x = 18 + 8z equation(4)
Replace equation(4) into equation(1)
-6x + 6y - 5z = -6 equation(1)
-(18 + 8z) + 6y -5z = -6
6y - 13z = 12
6x = 18 + 8z
6y - 13z = 12
Assume z = 0
:. x = 3 and y = 2
2007-04-28 06:05:01 · answer #2 · answered by chndr_vny 1 · 0⤊ 1⤋
-6x + 6y - 5z = - 6
12x - 6y + 12z = 24----ADD
6x + 7z = 18
4x - 2y + 4z = 8
2x + 2y - 12z = 10----ADD
6x - 8z = 18
-6x + 8z = - 18
6x + 7z = 18----Add
15z = 0
z = 0
6x = 18
x = 3
2x + 2y - 12z = 10
6 + 2y - 0 = 10
2y = 4
y = 2
x = 3, y = 2, z = 0
2007-04-28 03:25:14 · answer #3 · answered by Como 7 · 0⤊ 1⤋
5z=6-6x+6y=6(1-x+y)
z=(1-x+y)6/5
4z=8-4x+2y=2(4-2x+y)
z=(4-2x+y)/2
(4-2x+y)/2=(1-x+y)6/5
20-10x+5y=12-12x+12y
8+2x-7y=0
x=(7y-8)/2
Substitute x & z in the third equation and solve the system. It is easy.
Best of luck.
2007-04-28 03:30:26 · answer #4 · answered by Harsh 2 · 0⤊ 1⤋
x=3
y=2
z=0
2007-04-28 03:38:13 · answer #5 · answered by Sharon 2 · 0⤊ 1⤋
x = 3
y = 2
z = 0
HTH
Doug
2007-04-28 03:30:27 · answer #6 · answered by doug_donaghue 7 · 0⤊ 1⤋