Remark
Many calculators have a key that will do this in one step. Mine is one of them. So let's start with the answer and then we'll do it the long way.
9C3 = 84. You put it into your calculator as 9 2nF nCr 3 =
Solution

3*4*7 = 84 which is what you set out to show.
Answer:
the answer is false because 3 is multiplied with 5 on the right side
Then, when substitute any number , there remain difference
Answer:
depends on situations
Step-by-step explanation:
Yes you are correct.........
Answer:
Increasing
−5<x<−1
−1<x<1
Decreasing
4<x<7
−8<x<−5
Neither Increasing nor Decreasing
1<x<4
Step-by-step explanation: