Bạn ơi = 1820/243
( 5/1 + 5/243 ) + (5/9 + 5/81) + ( 5/3 + 5/27)
=1220\243+50\81+50\27
=1820\243
học tốt
1820/243 nhaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa bạn
Ta có
\(\left(\frac{5}{1}+\frac{5}{243}\right)+\left(\frac{5}{9}+\frac{5}{81}\right)+\left(\frac{5}{3}+\frac{5}{27}\right)\)
=\(\left(\frac{1215}{243}+\frac{5}{243}\right)+\left(\frac{45}{81}+\frac{5}{81}\right)+\left(\frac{45}{27}+\frac{5}{27}\right)\)
=\(\frac{1220}{243}+\frac{50}{81}+\frac{50}{27}\)
=\(\frac{1220}{243}+\frac{150}{243}+\frac{450}{243}\)
=\(\frac{1820}{243}\)
Đ/s là: 1820/243
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