Question

if the no. a b c d and e are in a.p. find value of a-4b +6c-4d+e

Answer 1

let d is the common difference and x is the first term of AP
a=x
b=x+d
c=x+2d
d=x+3d
e=x+4d
now ,
a-4b+6c-4d+e=x-4(x+d)+6 (x+2d)-4 (x+3d)+(x+4d)
=x-4x-4d+6x+12d-4x-12d+x+4d
=x-4x+6x-4x+x=0