6. If the set {[4311],[−20−4],[3a5]} in R3 is linearly independent, what value can a not be?
Set the determinant equal to zero and solve for 'a': −6a−6=0⇒a=−1
Step 1 :Form the matrix and calculate its determinant: |4−2330a11−45|=−6a−6
Step 2 :Set the determinant equal to zero and solve for 'a': −6a−6=0⇒a=−1