Need help on matrices using cramer's rule

AI Thread Summary
The discussion revolves around solving a system of equations using Cramer's rule, specifically the equations x - y + 3z = 8, 3x + y - 2z = -2, and 2x + 4y + z = 0. The user has calculated the solution as x = 1, y = -1, z = 2, and seeks clarification on whether this indicates a dependent equation. Responses confirm that the solution is unique and satisfies all equations, with the determinant of the coefficients not being zero. The consensus is that the user's solution is correct, and there is no dependency among the equations.
qdv
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I am learning how to solve a matrice using cramer's rule, and not sure if this is the correct answer.

Solve the following systems of equations
x - y + 3z = 8
3x + y - 2z = -2
2x + 4y + z = 0
so I figured out the solution is x = 1, y = -1, z = 2

but is this equation consider a
dependent equation that all solutions that satisfy x - y + 3z = 8 ??

thanks
 
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qdv said:
I am learning how to solve a matrice using cramer's rule, and not sure if this is the correct answer.

Solve the following systems of equations
x - y + 3z = 8
3x + y - 2z = -2
2x + 4y + z = 0
so I figured out the solution is x = 1, y = -1, z = 2

thanks

It's okay.The solution satisfies all equations and it's unique,therefore...Congratulations! :smile:

Daniel.
 
Online calculator

I solve it using a online calculator and I got

Cramer rule's solver step by step
Coeficients Matrix
1 -1 3 8
3 1 -2 -2
2 4 1 0
Δ = determinant1 -1 3
3 1 -2
2 4 1
Δ sub x = det8 -1 3
-2 1 -2
0 4 1
Δ sub y = det1 8 3
3 -2 -2
2 0 1
Δ sub z = det1 -1 8
3 1 -2
2 4 0
Δ = det1 -1 3
3 1 -2
2 4 1
1 -1 3
3 1 -2

[(1) (1) (1) + (3) (4) (3) + (2) (-1) (-2)] - [(3) (-1) (1) + (1) (4) (-2) + (2) (1) (3)]
(1) + (36) + (4)- (-3) + (-8) + (6)
( 41) - ( -5)
Δ = 46

Δx = det8 -1 3
-2 1 -2
0 4 1
8 -1 3
-2 1 -2

[(8) (1) (1) + (-2) (4) (3) + (0) (-1) (-2)] - [(-2) (-1) (1) + (8) (4) (-2) + (0) (1) (3)]
(8) + (-24) + (0)- (2) + (-64) + (0)
( -16) - ( -62)
Δx = 46

Δy = det1 8 3
3 -2 -2
2 0 1
1 8 3
3 -2 -2

[(1) (-2) (1) + (3) (0) (3) + (2) (8) (-2)] - [(3) (8) (1) + (1) (0) (-2) + (2) (-2) (3)]
(-2) + (0) + (-32)- (24) + (0) + (-12)
( -34) - ( 12)
Δy = -46

Δz = det1 -1 8
3 1 -2
2 4 0
1 -1 8
3 1 -2

[(1) (1) (0) + (3) (4) (8) + (2) (-1) (-2)] - [(3) (-1) (0) + (1) (4) (-2) + (2) (1) (8)]
(0) + (96) + (4)- (0) + (-8) + (16)
( 100) - ( 8)
Δz = 92

x =46/46

y =-46/46

z =-46/46

x =1

y =-1

z =2

-------
www.algebrasolver.totalh.com
 
Last edited:
qdv said:
I am learning how to solve a matrice using cramer's rule, and not sure if this is the correct answer.

Solve the following systems of equations
x - y + 3z = 8
3x + y - 2z = -2
2x + 4y + z = 0
so I figured out the solution is x = 1, y = -1, z = 2

but is this equation consider a
dependent equation that all solutions that satisfy x - y + 3z = 8 ??

thanks
What do you mean by "this equation"? It's not at all clear what your question is. Yes, as dextercioby said, and you could easily have checked, x= 1, y= -1, z= 2 satisfies the three equations and, since the determinant of coefficients is not 0, is the only solution to that system of equations.
 
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