\(a/\frac{7}{9}-\frac{x}{3}=\frac{1}{9}\)

\(\Rightarrow\frac{x}{3}=\frac{7}{9}-\frac{1}{9}\)

\(\Rightarrow\frac{x}{3}=\frac{2}{3}\)

\(\Rightarrow x=2\)

Vậy \(x=2\)

\(b/\frac{1}{x}-\frac{-2}{15}=\frac{7}{15}\)

\(\Rightarrow\frac{1}{x}=\frac{7}{15}+\frac{-2}{15}\)

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

\(\Rightarrow x=3\)

Vậy \(x=3\)

\(c/\frac{-11}{14}-\frac{-4}{x}=\frac{-3}{14}\)

\(\Rightarrow\frac{-4}{x}=\frac{-11}{14}-\frac{-3}{14}\)

\(\Rightarrow\frac{-4}{x}=\frac{-4}{7}\)

\(\Rightarrow x=7\)

Vậy \(x=7\)

\(d/\frac{x}{21}-\frac{2}{3}=\frac{5}{21}\)

\(\Rightarrow\frac{x}{21}=\frac{5}{21}+\frac{2}{3}\)

\(\Rightarrow\frac{x}{21}=\frac{19}{21}\)

\(\Rightarrow x=19\)

Vậy \(x=19\)

#Mạt Mạt#

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CẢM ƠN VƯƠNG MẠT MẠT NHA!

29-x/21 + 27-x/23 + 25-x/25 + 23-x/27 + 21-x/29 = -5

1 + 29-x/21 + 1 + 27-x/23 + 1 + 25-x/25 + 1 + 23-x/27 + 1 + 21-x/29 = 0 

50-x/21 + 50-x/23 + 50-x/25 + 50-x/27 + 50-x/29 = 0

(50-x) (1/21 + 1/23 + 1/25 + 1/27 + 1/29) = 0

Vì: 1/21 + 1/23 + 1/25 + 1/27 + 1/2 > 0

=> 50 - x = 0

             x = 50

Vậy x = 50

\(\frac{-1}{3}+\frac{0,2-0,3+\frac{5}{11}}{-0,3+\frac{9}{16}-\frac{15}{12}}\)

\(=\frac{-1}{3}+\frac{\frac{2}{10}-\frac{3}{10}+\frac{5}{11}}{\frac{-3}{10}+\frac{9}{16}-\frac{15}{12}}\)

\(=\frac{-1}{3}+\frac{\frac{39}{110}}{\frac{-79}{80}}\)

\(=\frac{-1}{3}-\frac{312}{869}\)

\(=\frac{-1805}{2607}\)

a)\(\left(\frac{3}{29}-\frac{1}{5}\right)\cdot\frac{29}{3}\)

\(=\left(\frac{3}{29}\cdot\frac{29}{3}\right)-\left(\frac{1}{5}\cdot\frac{29}{3}\right)\)

\(=1-\frac{29}{15}\)

\(=\frac{-14}{15}\)

b)\(\frac{16}{15}\cdot\frac{-5}{14}\cdot\frac{54}{24}\cdot\frac{56}{21}\)

=\(=\frac{16\cdot\left(-5\right)\cdot54\cdot56}{15\cdot14\cdot24\cdot21}\)

\(=\frac{2^4\cdot\left(-5\right)\cdot2\cdot3^3\cdot2^3\cdot7}{3\cdot5\cdot7\cdot2\cdot2^3\cdot3\cdot7}\)

\(=2^4\)

c)\(\frac{37}{7}\cdot\frac{8}{11}+\frac{37}{7}\cdot\frac{5}{11}-\frac{37}{7}\cdot\frac{2}{11}\)

\(=\frac{37}{7}\cdot\left(\frac{8}{11}+\frac{5}{11}-\frac{2}{11}\right)\)

\(=\frac{37}{7}\cdot1\)

\(=\frac{37}{7}\)

Đúng nhớ k nhen!

b)\(-2^4\)nãy mk nhầm

thank you cho mk xin nick fb của bn

\(\frac{29-x}{21}+\frac{27-x}{23}+\frac{25-x}{25}+\frac{23-x}{27}+\frac{21-x}{29}=-5.\)

\(\left(\frac{29-x}{21}+1\right)+\left(\frac{27-x}{23}+1\right)+\left(\frac{25-x}{25}+1\right)+\left(\frac{23-x}{27}+1\right)+\left(\frac{21-x}{29}+1\right)\)\(=0\)

\(\frac{50-x}{21}+\frac{50-x}{23}+\frac{50-x}{25}+\frac{50-x}{27}+\frac{50-x}{29}=0\)

\(\left(50-x\right).\left(\frac{1}{21}+\frac{1}{23}+\frac{1}{25}+\frac{1}{27}+\frac{1}{29}\right)=0\)

=> 50 - x = 0 \(\left(\frac{1}{21}+\frac{1}{23}+\frac{1}{25}+\frac{1}{27}+\frac{1}{29}\ne0\right)\)

=> x = 50

a)\(\frac{5}{21}\)+\(\frac{-3}{7}\)<\(\frac{x}{21}\)<\(\frac{-2}{7}\)+\(\frac{8}{21}\)

\(\Rightarrow\)\(\frac{-4}{21}\)<\(\frac{x}{21}\)<\(\frac{2}{21}\)

\(\Rightarrow\)\(\frac{x}{21}\)\(\in\)\(\left\{\frac{-3}{21};\frac{-2}{21};\frac{-1}{21};\frac{0}{21};\frac{1}{21}\right\}\)

vậy x\(\in\)\(\left\{-3;-2;-1;0;1\right\}\)

mấy câu kia cs tương tự ạ

bằng 2

đáp án đúng = 2

ms làm hôm nay xong

\(pt\Leftrightarrow\frac{29}{21}-\frac{x}{21}+\frac{27}{23}-\frac{x}{23}+\frac{25}{25}-\frac{x}{25}+\frac{23}{27}-\frac{x}{27}+\frac{21}{29}-\frac{x}{29}=-5\Leftrightarrow-x\left(\frac{1}{21}+\frac{1}{23}+\frac{1}{25}+\frac{1}{27}+\frac{1}{29}\right)=-5-\frac{29}{21}-\frac{27}{23}-\frac{25}{25}-\frac{23}{27}-\frac{21}{29}\Leftrightarrow-x=\frac{-5-\frac{29}{21}-\frac{27}{23}-\frac{25}{25}-\frac{23}{27}-\frac{21}{29}}{\frac{1}{21}+\frac{1}{23}+\frac{1}{25}+\frac{1}{27}+\frac{1}{29}}=-50\Leftrightarrow x=50\\ \Rightarrow S=\left\{50\right\}\)