Question: c > 2.5; c = 3

(1+x)

n

=

n

C

0

+

n

C

1

x+

n

C

2

x

2

+

n

C

3

x

3

+

n(1+x)

n−1

=

n

C

1

+2

n

C

2

x+3

n

C

3

x

2

+

Put x=5

n(1+5)

n−1

=C

1

+2.5C

2

+3.5

2

C

3

+

=n6

n−1

.

you can't solve x because it is 2 linear equation and you only have one equation