Efficient Method for Finding Basis and Determinant of 4 Vectors in Matrix Form

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I know how to do the problem, just put the 4 vectors in matrix form and find for what values of k is the detminant =0. the answer is then that k can't equal the value that was found.

Is there a easier way to do this?

My method involves finding the determinant using the expansion method, which seems like a long way. Is there a faster way?
 

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In this example, it's quicker to spot simplifications first.
Add 3rd vector to 2nd to produce (0, 2, 0, 7).
Multiply 1st by 7 and new 2nd by 2 then subtract 2nd from 1st.
etc.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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