Question

If ((n + 2) = 90 [(n); (n > 0), then the value of 'n' is :
(a) 9
(b) 8
(c) 10
(d) 7​

Answer 1

Answer:

Step-by-step explanation:

8 is the correct answer.

Hope it helps.

Answer 2

Answer:

Solution:

n

P  

2

​  

=90

or,  

(n−2)!

n!

​  

=90

or, n(n−1)=90

or, n  

2

−n−90=0

or, n  

2

−10n+9n−90=0

or, n(n−10)+9(n−10)=0

or, (n−10)(n+9)=0

or, n=10 or =n=−9

n can't be negative so, n=10.

Step-by-step explanation: