\(\left(\frac{2}{4}+\frac{-5}{3}\right)\cdot\frac{6}{5}\)

\(\Leftrightarrow\left(\frac{2}{4}-\frac{5}{3}\right)\cdot\frac{6}{5}\)

\(=\left(\frac{6}{12}-\frac{20}{12}\right)\cdot\frac{6}{5}\)

\(=\frac{-\left(6-20\right)}{12}\cdot\frac{6}{5}\)

\(=\frac{-7}{6}\cdot\frac{6}{5}\)

\(=\frac{-7\cdot6}{6\cdot5}\)

\(=\frac{-7}{5}\)

\(\left(\frac{2}{4}+\frac{-5}{3}\right).\frac{6}{5}\)

\(=\left(\frac{1}{2}+\frac{-5}{3}\right).\frac{6}{5}\)

\(=\left(\frac{3}{6}+\frac{-10}{6}\right).\frac{6}{5}\)

\(=\frac{-7}{6}.\frac{6}{5}\)

\(=\frac{-7}{5}\)

Ta có:

\(\frac{1}{2\cdot3}+\frac{1}{3\cdot4}+\frac{1}{4\cdot5}+...+\frac{1}{199\cdot200}\)

\(=\left(\frac{1}{2}-\frac{1}{3}\right)+\left(\frac{1}{3}-\frac{1}{4}\right)+\left(\frac{1}{4}-\frac{1}{5}\right)+...+\left(\frac{1}{199}-\frac{1}{200}\right)\)

\(=\frac{1}{2}+\left(\frac{1}{3}-\frac{1}{3}\right)+\left(\frac{1}{4}-\frac{1}{4}\right)+...+\left(\frac{1}{199}-\frac{1}{199}\right)+\frac{1}{200}\)

\(=\frac{1}{2}+0+0+...+0+\frac{1}{200}\)

\(=\frac{1}{2}+\frac{1}{200}\)

\(=\frac{1\cdot100}{2\cdot100}+\frac{1}{200}\)

\(=\frac{100}{200}+\frac{1}{200}\)

\(=\frac{101}{200}\)

\(\frac{1}{2}.\left(1-x\right)+\frac{2}{3}=1\)

\(\frac{1}{2}.\left(1-x\right)=1-\frac{2}{3}\)

\(\frac{1}{2}.\left(1-x\right)=\frac{1}{3}\)

\(1-x=\frac{1}{3}:\frac{1}{2}\)

\(1-x=\frac{1}{3}\times2\)

\(1-x=\frac{2}{3}\)

\(x=1-\frac{2}{3}\)

\(x=\frac{1}{3}\)

Vậy \(x=\frac{1}{3}\)

_HT_

Xin lỗi , mình gửi lại câu trả lời !

\(\frac{1}{2}.\left(1-x\right)+\frac{2}{3}=-1\)

\(\frac{1}{2}.\left(1-x\right)=\left(-1\right)-\frac{2}{3}\)

\(\frac{1}{2}.\left(1-x\right)=-\frac{5}{3}\)

\(1-x=-\frac{5}{3}:\frac{1}{2}\)

\(1-x=-\frac{10}{3}\)

\(x=1-\left(-\frac{10}{3}\right)\)

\(x=\frac{13}{3}\)

Vậy \(x=\frac{13}{3}\)

_HT_

\(\left(-84\right).3+\left(-7\right).24-2022\)

\(=-252-168-2022\)

\(=-420-2022\)

\(=-2442\)

TL:
-2442

bằng vô cực vì vô cực là số cực nhìu nên thế nha

hỏi cho vui thôi

Độ dài cạnh góc vuông còn lại là :

\(9,5:100\times40=3,8\left(cm\right)\)

Diện tích hình tam giác vuông đó là :

\(9,5\times3,8:2=18,05\left(cm^2\right)\)

  Đáp số : \(18,05cm^2\)

_HT_

Lời giải:

Độ dài cạnh góc vuông còn lại:

$9,5\times 40:100=3,8$ (cm) 

Diện tích hình tam giác vuông:

$3,8\times 9,5:2=18,05$ (cm²)

\(\left(x-1\right)^{10}=\left(x-1\right)^8\)

\(\left(x-1\right)^{10}-\left(x-1\right)^8=0\)

\(\left(x-1\right)^8\left[\left(x-1\right)^2-1\right]=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=1\\x=2\end{matrix}\right.\)

a, \(\dfrac{3}{8}+\left(-\dfrac{5}{8}\right)=\dfrac{3}{8}-\dfrac{5}{8}=-\dfrac{2}{8}=-\dfrac{1}{4}\)

b, \(-\dfrac{11}{24}-\dfrac{13}{24}=-\dfrac{24}{24}=-1\)