# Algebra help!

posted by
**Becca**
.

1.) Solve the system by triangularizing the augmented matrix and using back substitution.

-x-y+z=1

x-y-4z=-7

4x+y+z=6

2.) Perform the indicated row operation, then write the new matrix.

-4 4 | 4

9 -6 | 5 -2R1+ R2 ---> R2

3.) Solve the system by triangularizing the augmented matrix and using back substitution. If the system is linearly dependent, give the solution in terms of a parameter.

-x+y+z=0

3x+2y+5z=18

15x+10y+25z=89