\(x.\left(\frac{1}{4}+\frac{1}{5}\right)-\left(\frac{1}{7}+\frac{1}{8}\right)=0\)

\(x.\frac{9}{20}-\frac{15}{56}=0\)

\(x.\frac{9}{20}=0+\frac{15}{56}\)

\(x.\frac{9}{20}=\frac{15}{56}\)

\(x=\frac{15}{56}:\frac{9}{20}\)

\(x=\frac{25}{42}\)

Chúc bạn học tốt !!!

\(x\left(\frac{1}{4}+\frac{1}{5}\right)-\left(\frac{1}{7}+\frac{1}{8}\right)=0\)

\(x\left(\frac{5+4}{20}\right)-\left(\frac{8+7}{56}\right)=0\)

\(x.\frac{9}{20}-\frac{15}{56}=0\)

\(x.\frac{9}{20}=\frac{15}{56}\)

\(x=\frac{15}{56}:\frac{9}{20}\)

\(x=\frac{25}{42}\)

HOK TOT

\(\frac{1}{2016}< \frac{1+3}{2016+3}\)

#)Bạn ơi !

   Chỗ 2016..... là thế nào vậy ????? có ph 201620152014......1 không ???

Trả lời :

1 + 1 - 1 + 23 + 3333 + 3 + 86756757 = 86760117

~Study well~

#SJ

trả lời:

1+1-1+23+3333+3+86756757=86760117

#hok tốt#

1. when  I was  ten , I began  playing football.

2. in the future , my father will  go abroad.

3. reading books in my free time  is my  favourite  hobby.

4. I  think  skating is more  interesting than mountain - climbing.

5. I don't  know  why  my mother  cooked.     (nghe lạ, hình như còn đoạn sau à)

6. he  collects  books  whenever he has money.

7. How many paintings did she paint ?

8. I  love flowers, so I  plant  them around my house.

\(A=\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}....\frac{1}{99.100}\)

\(A=1-\frac{1}{100}\)

\(A=\frac{99}{100}\)

\(A=\frac{1}{1.2}+\frac{1}{2.3}+...+\frac{1}{99.100}\)

\(A=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{99}-\frac{1}{100}\)

\(A=1-\frac{1}{100}=\frac{99}{100}\)

P/s: Đề nghị ko đăng giúp tăng sp, đổi nhé. -_- 

Bạn tham khảo link này nhé :

https://olm.vn/hoi-dap/detail/55851056471.html

~Study well~

#SJ

\(\frac{5}{6}+\frac{5}{66}+\frac{5}{176}+\frac{5}{336}\)

\(=5\left(\frac{1}{6}+\frac{1}{66}+\frac{1}{176}+\frac{1}{336}\right)\)

\(=5\left(\frac{4}{21}\right)\)

\(=\frac{20}{21}\)

a) Vì Ot là tia phân giác của \(\widehat{xOy}\)nên \(\widehat{xOt}=\widehat{tOy}=\frac{\widehat{xOy}}{2}\)

Ta có: \(\hept{\begin{cases}\widehat{xOt'}+\widehat{xOt}=180^0\\\widehat{t'Oy}+\widehat{yOt}=180^0\end{cases}}\)

Mà \(\widehat{xOt}=\widehat{tOy}\left(cmt\right)\)nên \(\widehat{xOt'}=\widehat{t'Oy}\left(đpcm\right)\)

b) Vì Ot là tia phân giác của \(\widehat{xOy}\)nên \(\widehat{xOt}=\widehat{tOy}=\frac{\widehat{xOy}}{2}\)

Vì Om là tia phân giác của \(\widehat{x'Oy}\)nên \(\widehat{x'Om}=\widehat{mOy}=\frac{\widehat{x'Oy}}{2}\)

Mà \(\widehat{xOy}+\widehat{x'Oy}=180^0\)(kề bù) nên \(\widehat{tOy}+\widehat{mOy}=\frac{180^0}{2}\)

\(\Rightarrow\widehat{mOt}=90^0\)

Vậy \(\widehat{mOt}=90^0\)