PreCalculus
posted by Alexa
Solve the system of equations using matrices. Use Gaussian elimination with backsubstitution.
x + y + z = 5
x  y + 3z = 1
4x + y + z = 2
I really need help..
1 1 1 5
1 1 3 1
4 1 1 1 2
I've done so many different methods to solve this and I get stuck..

Reiny
agree with
1 1 1 5
1 1 3 1
4 1 1 2 > you had an extra 1 in there
1 1 1 5
0 2 2 4 #1  #2
0 3 3 18
1 1 1 5
0 1 1 2 #2 divided by 2
0 1 1 6 #3 divided by 3
1 1 1 5
0 1 1 2
0 0 2 4 #2  #3
1 1 1 5
0 1 1 2
0 0 1 2
from #3:
z = 2
in #2:
y  z = 2
y + 2 = 2
y = 4
in #1
x + y + z = 5
x  4  2 = 5
x = 1
x = 1, y = 4, z = 2 
Alexa
thank you!
Respond to this Question
Similar Questions

algebra
i need help with these problems (either a solution or how to plug them into a graphing calculator): 1) Solve by substitution or elimination 4/x + 1/y + 2/z = 4 2/x + 3/y  1/z = 1 1/x + 1/y + 1/z = 4 2)Solve the system of equations … 
pre  CALCULUS
Solve the system of equations using matrices. Use Gaussian elimination with back substitution. x+y+z = 5 xy+3z = 1 4x+y+z = 2 
precalc
Solve the system of equations using matrices. Use Gaussian elimination with back substitution. x+y+z = 5 xy+3z = 1 4x+y+z = 2 
precalc
Solve the system of equations using matrices. Use Gaussian elimination with back substitution. x+y+z = 5 xy+3z = 1 4x+y+z = 2 
HELP PLEASE
Solve the system of equations using matrices. Use Gaussian elimination with back substitution. x+y+z = 5 xy+3z = 1 4x+y+z = 2 
precalc  JAI
Solve the system of equations using matrices. Use Gaussian elimination with back substitution. x+y+z = 5 xy+3z = 1 4x+y+z = 2 
Pre calculus
olve the system of equations using matrices. Use Gaussian elimination with backsubstitution. x + y + z = 5 x  y + 3z = 1 4x + y + z = 2 I need it explained to me, how do I do this? 
pre calculus
Use Gaussian elimination to write the system of equations given below in rowechelon form 2x+4y+z=4 2x4y+6z=13 4x2y+z=6 
pre calculus
Use Gaussian elimination to write the system of equations given below in rowechelon form. 2x+4y+z=4 2x4y+6z=13 4x2y+z=6 
M240 Help please
Solve the following system of equations using matrices. Use Gaussian elimination with back substitution or GaussJordan elimination. a. 3x1 + 5x2  8x3 + 5x4 = 8 b. x1 + 2x2  3x3 + x4 = 7 c. 2x1 + 3x2  7x3 + 3x4 = 11 d. 4x1 + …