Answer:
x1=-4/5, x2=18/5 and x3=7/5
Step-by-step explanation:
[tex]\left[\begin{array}{ccc|c}1&0&-3&-5\\3&1&2&4\\2&2&1&7\end{array}\right][/tex]
you can do linear combination between the rows:
2nd row=R2-3R1 and 3th row=R3-2R1
[tex]\left[\begin{array}{ccc|c}1&0&-3&-5\\0&1&11&19\\0&2&7&17\end{array}\right][/tex]
3th row=(3R2-R3)/15
[tex]\left[\begin{array}{ccc|c}1&0&-3&-5\\0&1&11&19\\0&0&1&\frac{7}{5} \end{array}\right][/tex]
1st row=R1+3R3 and R2-11R3
[tex]\left[\begin{array}{ccc|c}1&0&0&-4/5 \\0&1&0&18/5 \\0&0&1&7/5\end{array}\right][/tex]
x1=-4/5, x2=18/5 and x3=7/5
