-1/4 + (-5/3)
When there is no number between a grouping symbol and a + or - sign, by default you can multiply the contents in the group by 1 to get rid of the grouping symbols.
If you would like to know the next value, you can calculate this using the following steps:
1/6, 1/9, 2/27, 4/81, x = ?
1/9 / 1/6 = 1/9 * 6 = 6/9 = 2/3
So, if we would like to know what is the next value of this geometric sequence, you have to multiply 4/81 by 2/3:
4/81 * 2/3 = 8/243
The correct result would be 8/243.
Answer:

Step-by-step explanation:
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Hope this helps you!
43 maybe? And if I’m wrong in advance-Sorry
Answer:
168
Step-by-step explanation:
2c(a+b) = 2 . 4 . (12 + 9) = 2 . 4 . 21 = 8 . 21 = 168