Answers and Step-by-step explanations:
9: (4/6) (-5/8)
This is just multiplication of fractions, so all you need to do is multiply both numerators by eachother and both denominators by eachother. Assuming that only the 5 is negative, (this is just an assumption since it's not clear which one is, or you can do the 8,) You get -20/48, since 4 x (-5) = -20, and 6 x 8 = 48. Simplify and you get -5/12.
10: (3/4) (-1/5)
Multiply the numerators, (3 and -1), and the denominators, (4 and 5,) to get -3/20. This is the lowest it can be simplified to, so therefore your answer is -3/20.
11. (-1/8) (-6/7)
Multiply -1 and -6 to get 6, (since two negatives make a positive.) Multiply the denominators, (8 and 7,) to get 56. This maks 6/56, which simplifies to 3/28.
12. (-4/9) (1/5)
Multiply the numerators, (-4 and 1,) to get -4. Multiply the denominators (9 and 5,) to get 45. Your answer is -4/45.
I'm really sorry if I'm wrong for anything, hope this helps! :)