Mn giúp mik nhé. Cảm ơn
Tính:
a) \(\dfrac{22}{33}\) + \(\dfrac{-444}{555}\) b) \(\dfrac{-123}{246}\) + \(\dfrac{-131313}{151515}\)
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\(\Leftrightarrow\dfrac{2}{3x}-\dfrac{780}{11}:\left[13\left(\dfrac{1}{15}+\dfrac{1}{35}+\dfrac{1}{63}+\dfrac{1}{99}\right)\right]=-5\)
\(\Leftrightarrow\dfrac{2}{3x}-\dfrac{780}{11}:\left[\dfrac{13}{2}\left(\dfrac{2}{15}+\dfrac{2}{35}+\dfrac{2}{63}+\dfrac{2}{99}\right)\right]=-5\)
\(\Leftrightarrow\dfrac{2}{3x}-\dfrac{780}{11}:\left[\dfrac{13}{2}\left(\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{9}+\dfrac{1}{9}-\dfrac{1}{11}\right)\right]=-5\)
\(\Leftrightarrow\dfrac{2}{3x}-\dfrac{780}{11}:\left[\dfrac{13}{2}\cdot\dfrac{8}{33}\right]=-5\)
\(\Leftrightarrow\dfrac{2}{3x}-45=-5\)
=>2/3x=40
=>3x=1/20
hay x=1/60
\(\dfrac{2}{3}x-70\dfrac{10}{11}:\left(\dfrac{131313}{151515}+\dfrac{131313}{353535}+\dfrac{131313}{636363}+\dfrac{131313}{999999}\right)=-5\\ \Rightarrow\dfrac{2}{3}x-\dfrac{780}{11}:\left(\dfrac{13}{15}+\dfrac{13}{35}+\dfrac{13}{63}+\dfrac{13}{99}\right)=-5\\ \Rightarrow\dfrac{2}{3}x-\dfrac{780}{11}:13\left(\dfrac{1}{15}+\dfrac{1}{35}+\dfrac{1}{63}+\dfrac{1}{99}\right)=-5\\ \Rightarrow\dfrac{2}{3}x-\dfrac{780}{11}:13.\dfrac{4}{33}=-5\\ \Rightarrow\dfrac{2}{3}x-\dfrac{780}{11}:\dfrac{52}{33}=-5\\ \Rightarrow\dfrac{2}{3}x-45=-5\\ \Rightarrow\dfrac{2}{3}x=40\\ \Rightarrow x=60\)
\(=>\dfrac{a}{b}\times\left(-\dfrac{2}{7}+\dfrac{5}{7}\right)=\dfrac{5}{7}\)
\(=>\dfrac{a}{b}\times\dfrac{3}{7}=\dfrac{5}{7}=>\dfrac{a}{b}=\dfrac{5}{7}:\dfrac{3}{7}=\dfrac{5}{3}\)
vậy \(\dfrac{a}{b}=\dfrac{5}{3}\)
\(\Rightarrow\dfrac{a}{b}\times\left(-\dfrac{2}{7}+\dfrac{5}{7}\right)=\dfrac{5}{7}\\ \Rightarrow\dfrac{a}{b}\times\dfrac{3}{7}=\dfrac{5}{7}\\ \Rightarrow\dfrac{a}{b}=\dfrac{5}{7}:\dfrac{3}{7}\\ \Rightarrow\dfrac{a}{b}=\dfrac{5}{3}\\ \Rightarrow a=5;b=3\)
\(\Leftrightarrow x\cdot\dfrac{3}{2}-\dfrac{780}{11}:\left[\dfrac{13}{15}+\dfrac{13}{35}+\dfrac{13}{63}+\dfrac{13}{99}\right]=-5\)
\(\Leftrightarrow x\cdot\dfrac{3}{2}-\dfrac{780}{11}:\left[\dfrac{13}{2}\left(\dfrac{2}{15}+\dfrac{2}{35}+\dfrac{2}{63}+\dfrac{2}{99}\right)\right]=-5\)
\(\Leftrightarrow x\cdot\dfrac{3}{2}-\dfrac{780}{11}:\left[\dfrac{13}{2}\left(\dfrac{1}{3}-\dfrac{1}{11}\right)\right]=-5\)
\(\Leftrightarrow x\cdot\dfrac{3}{2}-\dfrac{780}{11}:\dfrac{52}{33}=-5\)
\(\Leftrightarrow x\cdot\dfrac{3}{2}=40\)
hay x=40:3/2=80/3
Ngô Hải Nam ơi bn trả lời giúp mik ik
bài đó là bài 4^* tìm các số nguyên x để mỗi phân số sau đây là số nguyên
a. \(\dfrac{-18}{91}\) và \(\dfrac{-23}{114}\) ( mẫu chung : 10374 )
Quy đồng : \(\dfrac{-18}{91}=\dfrac{-2052}{10374}\) ; \(\dfrac{-23}{114}=\dfrac{-2093}{10374}\)
Vì \(\dfrac{-2052}{10374}>\dfrac{-2093}{10374}\Rightarrow\dfrac{-18}{91}>\dfrac{-23}{114}\)
Vậy...
b. \(\dfrac{-22}{35}\) và \(\dfrac{-103}{177}\) ( MC = 6195 )
Quy đồng : \(\dfrac{-22}{35}=\dfrac{-3894}{6195};\dfrac{-103}{177}=\dfrac{-3605}{6195}\)
Vì \(\dfrac{-3894}{6195}< \dfrac{-3605}{6195}\Rightarrow\dfrac{-22}{35}< \dfrac{-103}{177}\)
Vậy...
c. \(\dfrac{-22}{45}\) và \(\dfrac{-17}{33}\)(MC=495)
Quy đồng : \(\dfrac{-22}{45}=\dfrac{-242}{495};\dfrac{-17}{33}=\dfrac{-255}{495}\)
Vì \(\dfrac{-242}{495}>\dfrac{-255}{495}\Rightarrow\dfrac{-22}{45}>\dfrac{-17}{33}\)
Vậy
a, bạn tự làm
b, \(B=\dfrac{5^2}{5}\left(1-\dfrac{1}{6}+\dfrac{1}{6}-\dfrac{1}{11}+\dfrac{1}{11}-\dfrac{1}{16}+...+\dfrac{1}{101}-\dfrac{1}{106}\right)\)
\(=5\left(1-\dfrac{1}{106}\right)=\dfrac{5.105}{106}=\dfrac{525}{106}\)
c, đk : \(x\ne\dfrac{2}{3}\)
Ta có : \(\left|x-1\right|=2\Leftrightarrow\left[{}\begin{matrix}x=3\\x=-1\end{matrix}\right.\)(tm)
Với x = 3 suy ra \(C=\dfrac{2.9+9-1}{3.3-2}=\dfrac{26}{7}\)
Với x = -1 suy ra \(C=\dfrac{2-3-1}{-3-2}=\dfrac{-2}{-5}=\dfrac{2}{5}\)
6/21-(−12/44)+10/14−(1/(−4))−18/33
=2/7+12/44+5/7−((−1)/4)−6/11=2/7+12/44+5/7−((−1)/4)−6/11
=2/7+3/11+5/7+1/4−6/11=2/7+3/11+5/7+1/4−6/11
=(3/11−6/11)+(2/7+5/7)+1/4=(3/11−6/11)+(2/7+5/7)+1/4
=−3/11+7/7+1/4=−3/11+7/7+1/4
=43/44
a: \(\dfrac{22}{33}+\dfrac{-444}{555}=\dfrac{2}{3}-\dfrac{4}{5}=\dfrac{10}{15}-\dfrac{12}{15}=-\dfrac{2}{15}\)
b: \(\dfrac{-123}{246}+\dfrac{-131313}{151515}=\dfrac{-1}{2}+\dfrac{-13}{15}\)
\(=\dfrac{-15+\left(-26\right)}{30}=\dfrac{-41}{30}\)
a) 22/33 + (-444/555)
= 2/3 - 4/5
= -2/15
b) -123/246 + (-131313/151515)
= -1/2 - 13/15
= -41/30