Question

sum of x+5 observations is x^4-625.Find the mean.

Answer 1

Given, 

Number of observations = x + 5.

Sum of observations = x^4 - 625.

We know that Mean = sum of observations/Number of observations

                                   = x^4 - 625/x + 5

                                   = (x^2)^2 - 25^2/x + 5

                                    = (x^2 + 25)(x^2 - 25)/x + 5

                                    = (x^2 + 25)(x^2 - 5^2)/x + 5

                                    = (x^2 + 25)(x + 5)(x - 5)/(x + 5)

                                    = (x^2 + 25)(x - 5).


Note: (a + b)(a - b) = a^2 - b^2


Hope this helps!

Answer 2

Hi Vishu,

Please see the attached pic for step by step solution.


Hope it helped you.
Please let me know if any further doubt.
Cheers !!!
 :)