Giúp mik đi mik tick cho :
1, Tìm x:
a, x \(\div\) 2 + x \(\div\) 3 = x - 35
b, (\(\dfrac{1}{2\times4}\)+\(\dfrac{1}{4\times6}\)+\(\dfrac{1}{6\times8}\)+\(\dfrac{1}{8\times10}\)) \(\times\) x = \(\dfrac{1}{3}\)
2, Tính nhanh:
\(\dfrac{3}{2}\)\(\times\)\(\dfrac{3}{6}\) + \(\dfrac{3}{6}\)\(\times\)\(\dfrac{3}{10}\) + \(\dfrac{3}{10}\)\(\times\)\(\dfrac{3}{14}\) + ... + \(\dfrac{3}{42}\)\(\times\)\(\dfrac{3}{46}\)
Các bạn làm đc bài nào thì cứ làm giải hẳn ra hộ mik nha LOVE YOU~~
a) \(x:2+x:3=x-35\)
\(x-x:2-x:3=35\)
\(x\times1-x\times\dfrac{1}{2}-x\times\dfrac{1}{3}=35\)
\(x\times\left(1-\dfrac{1}{2}-\dfrac{1}{3}\right)=35\)
\(x\times\dfrac{1}{6}=35\)
\(x=35:\dfrac{1}{6}\)
\(x=210\)
b) \(\left(\dfrac{1}{2\times4}+\dfrac{1}{4\times6}+\dfrac{1}{6\times8}+\dfrac{1}{8\times10}\right)\times x=\dfrac{1}{3}\)
\(\left(\dfrac{2}{2\times4}+\dfrac{2}{4\times6}+\dfrac{2}{6\times8}+\dfrac{2}{8\times10}\right)\times x=\dfrac{2}{3}\)
\(\left(\dfrac{1}{2}-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{6}+\dfrac{1}{6}-\dfrac{1}{8}+\dfrac{1}{8}-\dfrac{1}{10}\right)\times x=\dfrac{2}{3}\)
\(\left(\dfrac{1}{2}-\dfrac{1}{10}\right)\times x=\dfrac{2}{3}\)
\(\dfrac{3}{10}\times x=\dfrac{2}{3}\)
\(x=\dfrac{2}{3}:\dfrac{3}{10}\)
\(x=\dfrac{20}{9}\)