Question

help me guyz plz...

what is the common difference of an A.P. in which A21-A7=84? ​

Answer 1

A21-A7=84

a+20d-(a+6d)=84

a+20d-a-6d=84

14d=84

d=84/14

d=6

Answer 2

Answer: d=6

Step-by-step explanation: a21= a+20d

a7= a+6d

a21 - a7= (a+20d) - (a+6d)= a+20d -a -6d= 84 ( a and -a get cancelled)

14d= 84

d=84/14

=6