\(F=\dfrac{12-\dfrac{36}{17}+\dfrac{24}{25}}{15-\dfrac{45}{17}+\dfrac{30}{25}}\)
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.


\(a,MSC:180\\ \dfrac{17}{12}=\dfrac{17.15}{12.15}=\dfrac{255}{180};\dfrac{31}{18}=\dfrac{31.10}{18.10}=\dfrac{310}{180};\dfrac{8}{15}=\dfrac{8.12}{15.12}=\dfrac{96}{180}\\ b,MSC:75\\ \dfrac{7}{15}=\dfrac{7.5}{15.5}=\dfrac{35}{75};\dfrac{8}{25}=\dfrac{8.3}{25.3}=\dfrac{24}{75};\dfrac{11}{75}=\dfrac{11}{75}\)

1) âm năm phần 12
2) âm mười bảy phần 9
3) -1
Đây là đáp án còn làm bài từ làm nhé

\(a,\dfrac{-15}{17}=-1+\dfrac{2}{17}\\ -\dfrac{19}{21}=-1+\dfrac{2}{21}\\ Vì:\dfrac{2}{17}>\dfrac{2}{21}\Rightarrow-1+\dfrac{2}{17}>-1+\dfrac{2}{21}\Rightarrow-\dfrac{15}{17}>-\dfrac{19}{21}\\ b,-\dfrac{24}{35}=-1+\dfrac{11}{35};-\dfrac{19}{30}=-1+\dfrac{11}{30}\\ Vì:\dfrac{11}{35}< \dfrac{11}{30}\Rightarrow-1+\dfrac{11}{35}< -1+\dfrac{11}{30}\\ \Rightarrow-\dfrac{24}{35}< -\dfrac{19}{30}\)

\(\dfrac{x-90}{10}+\dfrac{x-76}{12}=\dfrac{x-58}{14}+\dfrac{x-36}{16}+\dfrac{x-15}{17}=15\)
\(\Leftrightarrow\left(\dfrac{x-90}{10}-1\right)+\left(\dfrac{x-76}{12}-2\right)=\left(\dfrac{x-58}{14}-3\right)+\left(\dfrac{x-36}{16}-4\right)+\left(\dfrac{x-15}{17}-5\right)\)\(\Leftrightarrow\dfrac{x-100}{10}+\dfrac{x-100}{12}=\dfrac{x-100}{14}+\dfrac{x-100}{16}+\dfrac{x-100}{17}\)
\(\Leftrightarrow\left(x-100\right)\left(\dfrac{1}{10}+\dfrac{1}{12}-\dfrac{1}{14}-\dfrac{1}{16}-\dfrac{1}{17}\right)=0\)
\(\Leftrightarrow x-100=0\)
\(\Rightarrow x=100\)
Vậy \(S=\left\{100\right\}\)

\(\dfrac{15}{25}=\dfrac{15:5}{25:5}=\dfrac{3}{5}\\ \dfrac{24}{28}=\dfrac{24:4}{28:4}=\dfrac{6}{7}\\ \dfrac{18}{33}=\dfrac{18:3}{33:3}=\dfrac{6}{11}\\ \dfrac{12}{36}=\dfrac{12:12}{36:12}=\dfrac{1}{3}.\)

Câu a:
\(\frac27\) + \(\frac{-3}{8}\) + \(\frac{11}{7}\) + \(\frac17\) + \(\frac{5}{-8}\)
= (\(\frac27+\frac{11}{7}+\frac17\)) -(\(\frac38\) + \(\frac58\))
= (\(\frac{13}{7}+\frac17\)) - \(\frac88\)
= \(\frac{14}{7}-1\)
= 2 - 1
= 1
Câu b:
\(\frac{3}{17}+\frac{-5}{13}+\frac{-18}{35}+\frac{14}{17}+\frac{17}{-35}+\frac{-8}{13}\)
= (\(\frac{3}{17}+\frac{14}{17}\)) - (\(\frac{5}{13}\) + \(\frac{8}{13}\)) - (\(\frac{18}{35}+\frac{17}{35}\))
= \(\frac{17}{17}-\frac{18}{18}-\) \(\frac{35}{35}\)
= 1 - 1 - 1
= 0 - 1
= -1

\(=\left(\dfrac{3}{4}+\dfrac{1}{4}\right)+\left(-\dfrac{17}{25}-\dfrac{8}{25}\right)+\left(\dfrac{13}{37}+\dfrac{24}{37}\right)=1\)
\(F=\dfrac{12-\dfrac{36}{17}+\dfrac{24}{25}}{15-\dfrac{45}{17}+\dfrac{30}{25}}=\dfrac{12\left(1-\dfrac{3}{17}+\dfrac{2}{25}\right)}{15\left(1-\dfrac{3}{17}+\dfrac{2}{25}\right)}\)
\(=\dfrac{12}{15}=\dfrac{4}{5}\)
\(F=\dfrac{12-\dfrac{36}{17}+\dfrac{24}{25}}{15-\dfrac{45}{17}+\dfrac{30}{25}}\)
\(F=\dfrac{12.1-\dfrac{12.3}{17}+\dfrac{12.2}{25}}{15.1-\dfrac{15.3}{17}+\dfrac{15.2}{25}}\)
\(F=\dfrac{12.\left(1-\dfrac{3}{17}+\dfrac{2}{25}\right)}{15.\left(1-\dfrac{3}{17}+\dfrac{2}{25}\right)}\)
\(F=\dfrac{12.1}{15.1}\)
\(F=\dfrac{12}{15}\)
\(F=\dfrac{4}{5}\)