I assume the first equation is supposed to be
and not
As an augmented matrix, this system is given by
Multiply through row 3 by 1/2:
Add -1(row 2) to row 3:
Multiply through row 3 by 1/5:
Add -2(row 3) to row 1, and add 3(row 3) to row 2:
Add -3(row 2) to row 1:
Multiply through row 1 by -1:
Add -2(row 1) to row 2:
Multipy through row 2 by -1:
The solution to the system is then