86 Form 6F
_____ 11. Cramer‘s Rule will give the solution for all systems of two linear equations
unless:
a. the system has a unique solution. c. the coefficient determinant is zero.
b. is zero. d. Both and are zero.
_____ 12. Solve using any matrix method: Fifty percent of the boys and sixty percent of
the girls who attend Rothschild High School went to a recent pep-rally. The
total number of students at the pep-rally was 320. If there are 590 students
who attend Rothschild High, how many of these students are boys?
a. 250 b. 340 c. 324 d. 430
_____ 13. Which of the following statements is false in general for a matrix ?
I. | | is always non-negative.
II. The determinant of can only be found if is a square matrix.
III. To find the determinant of a 3 3 matrix, a sign array is used.
a. I only b. II only c. III only d. I and II
_____ 14. Consider the matrix . What is the minor for ?
a. b. c. d.
_____ 15. What is the determinant of the coefficient matrix for the system:
a. 9 b. 5 c. 5 d. 7
_____ 16. If and , find | | .
a. b. c. d.