## Solutions to Try Its

1. $\left(3,-7\right)$

2. $-10$

3. $\left(-2,\frac{3}{5},\frac{12}{5}\right)$

## Solutions to Odd-Numbered Exercises

1. A determinant is the sum and products of the entries in the matrix, so you can always evaluate that product—even if it does end up being 0.

3. The inverse does not exist.

5. $-2$

7. $7$

9. $-4$

11. $0$

13. $-7,990.7$

15. $3$

17. $-1$

19. $224$

21. $15$

23. $-17.03$

25. $\left(1,1\right)$

27. $\left(\frac{1}{2},\frac{1}{3}\right)$

29. $\left(2,5\right)$

31. $\left(-1,-\frac{1}{3}\right)$

33. $\left(15,12\right)$

35. $\left(1,3,2\right)$

37. $\left(-1,0,3\right)$

39. $\left(\frac{1}{2},1,2\right)$

41. $\left(2,1,4\right)$

43. Infinite solutions

45. $24$

47. $1$

49. Yes; 18, 38

51. Yes; 33, 36, 37

53. $7,000 in first account,$3,000 in second account.