Question

hey guys plz help me ........
thanks in advance if u would help me.....
plz help.....

Answer 1

we know that

X=(x1+x2+x3.......xn)/n            -eq1

similarly if we subtract 'a' from each term then

(x1-a+x2-a+x3-a.......xn-a)/n

=(x1+x2+x3.........xn-(a+a+a.....n terms))/n                  (cause we subtracted a fom n terms)

=(x1+x2+x3.........xn-(a*n))/n

=(x1+x2+x3.........xn)/n - (a*n)/n

=X-a     (from eq 1)