Question

Help with these questions

Answer 1

9514 1404 393

Answer:

  16) No

  17)  (c)

Step-by-step explanation:

For a lot of multiple-choice matrix problems, a simple test is all that is needed to determine the correct answer.

16) The determinant of A is (-2)(-2) -(2)(-3) = 10. So, we expect to see values in the inverse matrix that are 0.2 and 0.3. Alas, they're not there. The matrices are not inverses.

  A^-1 = [[-.2, .3][-.2, -.2]]

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17) The matrices are both 3×3, so their product is possible (eliminates choice D). The upper left term is different among the answer choices, so we can determine the correct one by computing that term only.

  BA=C

  c11 = (5)(1) +(7)(5) +(3)(-1) = 5 +35 -3 = 37

This matches the third choice (C).

If you use a calculator to compute the full matrix product, it matches choice C in all details.