Any 10th grader solve it
for 50 points

 is proved for the sum of pth, qth and rth terms of an arithmetic progression are a, b,and c respectively.

Step-by-step explanation:

Given that the sum of pth, qth and rth terms of an arithmetic progression are a, b and c respectively.

First term of given arithmetic progression is A

and common difference is D

ie., and common difference=D

The nth term can be written as

pth term of given arithmetic progression is a

qth term of given arithmetic progression is b

and

rth term of given arithmetic progression is c

We have to prove that

Now to prove LHS=RHS

Now take LHS

ie.,

Therefore

ie.,  

Hence proved

a reflection across the x axis and a 90 degree rotation left and right.