Question

How would i solve...

Solve the following system of equations.

x + 4y + z = –10
3x – 3y + 6z = –21
x + 2y + 2z = –10

I am thinking that I would have to multiply the first and third equation by 3?

Answer 1

use cramer's elimination method for three variables

Answer 2

what that?

Answer 3

umm i think it would better if u it googled it...it would be lengthy to explain i:-)t here...but its very easy

Answer 4

whats the first step?

Answer 5

i get 9x+15y+3z=-81?

Answer 6

You should the Gauss-Jordan method for elimination. If you can try and see this video for help, www.youtube.com/watch?v=JwT1FrLzEOQ

Answer 7

thanks, but i need to show my work. maybe with a fresh brain in the morning i can figure this out

Answer 8

1 4 1 -10
3 -3 6 -21
1 2 2 -10

R2 - 3R1
R3 - R1

1 4 1 -10
0 -15 3 9
0 -2 1 0

R3 - (2/15)R1

1 4 1 -10
0 -15 3 9
0 0 0.6 -1.2

R3 / 0.6

1 4 1 -10
0 -15 3 9
0 0 1 -2

R2 - 3R3

1 4 1 -10
0 -15 0 15
0 0 1 -2

R2 / 15

1 4 1 -10
0 -1 0 1
0 0 1 -2

R1 + 4R2
R1 - R3

1 0 0 -4
0 -1 0 1
0 0 1 -2

R2 / -1

1 0 0 -4
0 1 0 -1
0 0 1 -2
x=-4
y=-1
z=-2