Question

rút gọn A= 1+5+5^2+...+5^50

ai giúp mik vs

Answer 1

A=1+5+5²+5³+...+5⁵⁰

=> 5A=(5+5²+5³+...+5⁵⁰)+5⁵¹

=> 5A-A=5⁵¹-1 

4A=5⁵¹-1  => \(A=\frac{5^{51}-1}{4}\)

Answer 2

cảm ơn bạn nhé

Answer 3

\(A=1+5+5^2+....+5^{50}\)

\(5A=5+5^2+....+5^{50}+5^{51}\)

\(5A-A=\left(5+5^2+....+5^{50}+5^{51}\right)-\left(1+5+5^2+....+5^{50}\right)\)

\(4A=5^{51}-1\)

\(\Rightarrow A=\frac{5^{51}-1}{4}\)