Question

[Chu vinh thanh]

[( 5³/ 8.13) + ( 5³/ 13.18) +(5³/ 18.23) +.....+ (5³/ 93.98)].\(3\frac{17}{125}\)

Giúp mk với nhé!

Answer 1

[Trần Việt Anh]

Có:

\(\frac{5^3}{8.13}+\frac{5^3}{13.18}+...+\frac{5^3}{93.98}\)

= \(5^2\left(\frac{5}{8.13}+\frac{5}{13.18}+...+\frac{5}{93.98}\right)\)

=\(25\left(\frac{1}{8}-\frac{1}{13}+\frac{1}{13}-\frac{1}{18}+...+\frac{1}{93}-\frac{1}{98}\right)\)

=\(25\left(\frac{1}{8}-\frac{1}{98}\right)\)

=\(\frac{1125}{392}\)

=> \(\frac{1125}{392}.3\frac{17}{125}\)

= ...

Answer 2

[Chu vinh thanh]

cảm ơn bạn nhá!