SOLUTION: Short answer. Write the word or phrase that best completes each statement or answers the question. Find the value of k if you have the matrix: 5,9 -2,k = 8 I can't seem

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Question 89891This question is from textbook Algegra & Trigonometry
: Short answer. Write the word or phrase that best completes each statement or answers the question.
Find the value of k if you have the matrix:
5,9
-2,k = 8
I can't seem to even get going on this one. Not sure what to do.
Thanks,
Annie C. This question is from textbook Algegra & Trigonometry

Found 2 solutions by stanbon, Annie C:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
5,9
-2,k = 8
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I think your problem says "the determinant = 8
--------------
If that is true, the determinant is 5*k-9*-2 = 8
5k-18 = 8
5k = 26
k = 26/5 = 5 1/5
=====================
Cheers,
Stan H.

Answer by Annie C(1) About Me  (Show Source):
You can put this solution on YOUR website!
Solve by using the determinant:
5(k-(-18)= 8

5k+18=8
-18 -18
5k =-10

k=-2