Q. If A1, A2 are two AMs between two numbers a and b, then (2A1 - A2) ( 2A​2 - A1) is equal to 
(A) a + b                (B)  a b a   +   b                 (C) ab                  (D)  a   + b a b

Dear Student,

If A1 and A2 are two AM's of a and b then,As we know,a, A1 ,A2 ,b are in A.PSo, b+3dNow,Common difference d=b-a3A1=a+d= a+(b-a)3=2a+b3and,A2=a+2d= a+2b-a3= a+2b3now,2A1-A22A2-A1= 22a+b3-a+2b32a+2b3-2a+b3=4a+2b-a-2b32a+4b-2a-b3=3a3×3b3=abSo, option C is the correct answer.

Hope,you will find this helpful.

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