If M is the mean of x1, x2, x3, x4, x5 and x6, prove that(x1 − M) + (x2 − M) (x3 − M) (x4 − M) + (x5 − M) + (x6 − M) = 0.

If M is the mean of x1, x2, x3, x4, x5 and x6, prove that(x1 − M) +

1.	If M is the mean of x1, x2, x3, x4, x5 and x6, prove that(x1 − M) + (x2 − M) (x3 − M) (x4 − M) + (x5 − M) + (x6 − M) = 0.
Answer» If M is the mean of x₁, x₂, x₃, x₄, x₅ and x₆, prove that (x₁ − M) + (x₂ − M) (x₃ − M) (x₄ − M) + (x₅ − M) + (x₆ − M) = 0.