Question

[lê bá quốc minh]

Tìm x :

( 2/31*33 + 2/33*35 + ....... + 2/39*41 ) * 2542 - 2,04 : x = 19

Answer 1

[Xyz OLM]

\(\left(\frac{2}{31\times33}+\frac{2}{33\times35}+...+\frac{2}{39\times41}\right)\times2542-2,04:x=19\)

\(\Rightarrow\left(\frac{1}{31}-\frac{1}{33}+\frac{1}{33}-\frac{1}{35}+...+\frac{1}{39}-\frac{1}{41}\right)\times2542-2,04:x=19\)

\(\Rightarrow\left(\frac{1}{31}-\frac{1}{41}\right)\times2542-2,04:x=19\)

\(\Rightarrow\frac{10}{1271}\times2542-2,04:x=19\)

\(\Rightarrow20-2,04:x=19\)

\(\Rightarrow2,04:x=20-19\)

\(\Rightarrow2,04:x=1\)

\(\Rightarrow x=2,04:1\)

\(\Rightarrow x=2,04\)

Vậy x = 2,04

Answer 2

[︵✰ßล∂]

\(\left(\frac{2}{31\text{ x }33}+\frac{2}{33\text{ x }35}+...+\frac{2}{39\text{ x }41}\right)\text{ x }2542-2,04\text{ : }x=19\)

\(\left(\frac{1}{31}-\frac{1}{33}+\frac{1}{33}-\frac{1}{35}+...+\frac{1}{39}-\frac{1}{41}\right)\text{ x }2542-2,04\text{ : }x=1\)

\(\left(\frac{1}{31}-\frac{1}{41}\right)\text{ x }2542-2,04\text{ : }x=1\)

\(\frac{10}{1271}\text{ x }2542-2,04\text{ : }x=1\)

\(20-2,04\text{ : }x=1\)

\(2,04\text{ : }x=20-1\)

\(2,04\text{ : }x=19\)

\(x=2,04\text{ : }19\)

\(x=\frac{51}{475}\)