Question

The sum of (x+3) observations is (x to the power 4 - 81).Find the mean of the observation

Answer 1

X⁴−81 = (X²)²−9²

= (X²+9)(X²−9)

=(X+9)(X²−3²)

=(X+9)(X+3)(X-3)

SO MEAN = (X+9)(X+3)(X-3) / X+3

MEAN = (X+9)(X-3)