Question

Someone please help me to find the z-value

Answer 1

z = 5

Explanation:

It usually works well to do what the problem statement tells you. We don't have access to your matrix tool, so we've used a calculator instead. (See attached.)

Of course, the augmented matrix looks like ...

`\left[\begin{array}ccc-1&2&2&3\\3&1&-1&2\\2&1&1&9\end{array}\right]`