SOLUTION: If 5²×5⁴×5⁶×…×5²ᵃ=(0.04)⁻²⁸,how to determine the value of a? thanks u so much tutor ^^,it is a arithmetic progression.

Algebra ->  Sequences-and-series -> SOLUTION: If 5²×5⁴×5⁶×…×5²ᵃ=(0.04)⁻²⁸,how to determine the value of a? thanks u so much tutor ^^,it is a arithmetic progression.       Log On


   

Question 888130: If 5²×5⁴×5⁶×…×5²ᵃ=(0.04)⁻²⁸,how to determine the value of a? thanks u so much tutor ^^,it is a arithmetic progression.

Answer by luke94(89) About Me  (Show Source):
You can put this solution on YOUR website!
trial and error to achieve your answer:
(0.04)^-28 = 1.3877787807814456755295395851135e+39 or 1.4x10^39
having known that keep punching numbers in till you get the same answer which is 5^56 and in the question as stated is 5^2a divide 56 by 2 and your value of a is 23