2 câu trả lời
Đáp án:
$\dfrac{3}{20}+\dfrac{3}{30}+\dfrac{3}{42}+\dfrac{3}{56}+\dfrac{3}{72}+\dfrac{3}{90}$ $=\dfrac{9}{20}$
Giải thích các bước giải:
$\dfrac{3}{20}+\dfrac{3}{30}+\dfrac{3}{42}+\dfrac{3}{56}+\dfrac{3}{72}+\dfrac{3}{90}$
$=\dfrac{3}{20}+\dfrac{1}{10}+\dfrac{1}{14}+\dfrac{3}{56}+\dfrac{1}{24}+\dfrac{1}{30}$
$=\dfrac{126}{840}+\dfrac{84}{840}+\dfrac{60}{840}+\dfrac{45}{840}+\dfrac{35}{840}+\dfrac{28}{840}$
$=\dfrac{126+84+60+45+35+28}{840}$
$=\dfrac{378}{840}$
$=\dfrac{9}{20}$
Đáp án&
Giải thích các bước giải:
3/20+3/30+3/42+3/56+3/72+3/90=3/20+3/30+(3/42+3/72)+3/56+3/90=3/20+3/30+(3/114+3/56)+3/90=3/170+3/90=3/260
Cho mik 5 sao+tim+ctlhn.
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