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\(1)\dfrac{179}{50}-\left(\dfrac{59}{30}+\dfrac{3}{5}\right)\)
\(=\dfrac{179}{50}-\left(\dfrac{118}{60}+\dfrac{36}{60}\right)\)
\(=\dfrac{179}{50}-\dfrac{77}{30}\)
\(=\dfrac{537}{150}-\dfrac{385}{150}\)
\(=\dfrac{152}{150}=\dfrac{76}{75}=1\dfrac{1}{75}\)
Câu 1 : Ta có : 179/50 - ( 59/30 + 3/5 ) .
= 179/50 - ( 59/30 + 18/30 ) .
= 179/50 - 77/30 .
= 537/150 - 385/150.
= 76/75 .
Câu 2 : Ta có : ( 3,5 - 70,84 : 23 + 4 ) - 3,375 . 4/9 : 0,78 .
= ( 3,5 - 3,08 + 4 ) - 27/8 . 4/9 : 39/2 .
= 4,42 - 3/2 . 2/39 .
= 221/50 - 1/13 .
= 2873/650 - 50/650 .
= 2823/50 .
= 56,46 .
1.
\(\dfrac{30}{100}.x+\dfrac{1}{4}=\dfrac{1}{5}.x-\dfrac{1}{2}\)
\(\dfrac{3}{10}.x=\dfrac{1}{5}.x-\dfrac{1}{2}-\dfrac{1}{4}\)
\(\dfrac{3}{10}.x=\dfrac{1}{5}.x-\dfrac{1}{4}\)
\(\dfrac{1}{5}.x-\dfrac{3}{10}.x=\dfrac{1}{4}\)
\(\left(\dfrac{1}{5}-\dfrac{3}{10}\right).x=\dfrac{1}{4}\)
\(\dfrac{-1}{10}.x=\dfrac{1}{4}\)
\(x=\dfrac{1}{4}:\dfrac{-1}{10}\)
x=\(\dfrac{5}{-2}\)=\(\dfrac{-5}{2}\)
2.
\(\left(\dfrac{1}{7.9}+\dfrac{1}{9.11}+...+\dfrac{1}{31.33}\right).x=\left(0,25-3,5\right).\dfrac{27}{3}\)
\(\dfrac{2}{2}.\left(\dfrac{1}{7.9}+\dfrac{1}{9.11}+...+\dfrac{1}{31.33}\right).x=-3,25.9\)
\(\dfrac{1}{2}.\left(\dfrac{2}{7.9}+\dfrac{2}{9.11}+...+\dfrac{2}{31.33}\right).x=-29,25\)
\(\dfrac{1}{2}.\left(\dfrac{1}{7}-\dfrac{1}{33}\right).x=-29,25\)
\(\dfrac{1}{2}.\dfrac{26}{231}.x=-29,25\)
\(\dfrac{13}{231}.x=-29,25\)
\(x=-29,25:\dfrac{13}{231}\)
\(x=\dfrac{-2079}{4}\)
tick mink nha :)
F=(9.75.21\(\dfrac{3}{7}\)+\(\dfrac{39}{4}\).18\(\dfrac{4}{7}\)).\(\dfrac{15}{78}\)
=(\(\dfrac{39}{4}\).21\(\dfrac{3}{7}\)+\(\dfrac{39}{4}\).18\(\dfrac{4}{7}\)).\(\dfrac{15}{78}\)
=[\(\dfrac{39}{4}\).(21\(\dfrac{3}{7}\)+18\(\dfrac{4}{7}\))].\(\dfrac{15}{78}\)
=[\(\dfrac{39}{4}\).(21+18)+(\(\dfrac{3}{7}\)+\(\dfrac{4}{7}\))].\(\dfrac{15}{78}\)
=[\(\dfrac{39}{4}\).(39+1)].\(\dfrac{15}{78}\)
=(\(\dfrac{39}{4}\).40).\(\dfrac{15}{78}\)
=390.\(\dfrac{15}{78}\)=75
\(B=71\dfrac{38}{45}-\left(43\dfrac{8}{45}-1\dfrac{17}{57}\right)\)
\(B=71\dfrac{38}{45}-43\dfrac{8}{45}-1\dfrac{17}{57}\)
\(B=28\dfrac{2}{3}-1\dfrac{17}{57}=27\dfrac{11}{57}\)
\(D=\left(19\dfrac{5}{8}:\dfrac{7}{12}-13\dfrac{1}{4}:\dfrac{7}{12}\right).\dfrac{4}{5}\)
\(D=\dfrac{12}{7}.\left(19\dfrac{5}{8}-13\dfrac{1}{4}\right).\dfrac{4}{5}\)
\(D=\dfrac{12}{7}.\dfrac{51}{8}.\dfrac{4}{5}=\dfrac{306}{35}\)
Câu còn lại làm tương tự!
Chúc bạn học tốt!!!
(3,5+2x)\(\times\dfrac{8}{3}=5\dfrac{1}{3}\)
=\(\left(\dfrac{7}{2}+2x\right)\times\dfrac{8}{3}=\dfrac{16}{3}\)
=\(\dfrac{7}{2}\times\dfrac{8}{3}+2x\times\dfrac{8}{3}=\dfrac{16}{3}\)
\(2x\times\dfrac{8}{3}=\dfrac{16}{3}-\dfrac{7}{2}\times\dfrac{8}{3}\)
\(2x\times\dfrac{8}{3}=-4\)
\(2x=-4:\dfrac{8}{3}\)
\(2x=\dfrac{-3}{2}\)
\(x=\dfrac{-3}{2}:2\)
\(x=\dfrac{-3}{4}\)
\(\left(3.5+2x\right)\times\dfrac{8}{3}=5\dfrac{1}{3}\)
\(\Rightarrow\left(3.5+2x\right)=\dfrac{16}{3}\times\dfrac{8}{3}=\dfrac{128}{9}\)
\(\Rightarrow2x=\dfrac{128}{9}-3.5\)
|x/2-1|=3
=>x/2-1=3 hoặc -3
=>x/2= 4 hoặc -2
=>x:2=4 hoặc -2
=>x=2 hoặc -1
b,|x2x2-1|=3 \(\Leftrightarrow\left[{}\begin{matrix}\dfrac{x}{2}-1=3\\\dfrac{x}{2}-1=-3\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}\dfrac{x}{2}=4\\\dfrac{x}{2}=-2\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}x=2\\x=-1\end{matrix}\right.\)
c, |-x+2525|+1212=3,5 \(\Leftrightarrow\left|-x+\dfrac{2}{5}\right|=3,5-\dfrac{1}{2}\) \(\Leftrightarrow\left|-x+\dfrac{2}{5}\right|=3\) \(\Leftrightarrow\left[{}\begin{matrix}-x+\dfrac{2}{5}=3\\-x+\dfrac{2}{5}=-3\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{13}{5}\\x=\dfrac{-7}{2}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}-x=\dfrac{-13}{5}\\-x=\dfrac{7}{2}\end{matrix}\right.\)
\(\left|x-3,5\right|=7,5\)
\(\Leftrightarrow x-3,5=7,5\Rightarrow x=11\)
\(\Leftrightarrow x-3,5=-7,5\Rightarrow x=-4\)
\(\left|x+\dfrac{4}{5}\right|-\dfrac{1}{2}=0\)
\(\Leftrightarrow\left|x+\dfrac{4}{5}\right|=\dfrac{1}{2}\)
\(\Leftrightarrow x+\dfrac{4}{5}=\dfrac{1}{2}\Rightarrow x=\dfrac{-3}{10}\)
\(\Leftrightarrow x+\dfrac{4}{5}=-\dfrac{1}{2}\Rightarrow x=\dfrac{-13}{10}\)
\(3,6-\left|x-0,4\right|=0\)
\(\Leftrightarrow\left|x-0,4\right|=3,6\)
\(\Leftrightarrow x-0,4=3,6\Rightarrow x=4\)
\(\Leftrightarrow x-0,4=-3,6\Rightarrow x=-3,2\)
\(a,\dfrac{7}{35},\dfrac{18}{54},\dfrac{-15}{125},\dfrac{-4}{25}\)
Các thừa số đã tối giản : \(\dfrac{-4}{25}\)
\(\dfrac{7}{35}=\dfrac{7:7}{35:7}=\dfrac{1}{5}\) , \(\dfrac{18}{54}=\dfrac{18:18}{54:18}=\dfrac{1}{3}\)
\(\dfrac{-15}{125}=\dfrac{-15:5}{125:5}=\dfrac{-3}{25}\)
\(b,\dfrac{27}{45},\dfrac{21}{28},\dfrac{8}{14},\dfrac{18}{-60},\dfrac{-270}{360}\)
Các thừa số đã tối giản là : ko có
\(\dfrac{27}{45}=\dfrac{27:9}{45:9}=\dfrac{3}{5}\) , \(\dfrac{21}{28}=\dfrac{21:7}{28:7}=\dfrac{3}{4}\)
\(\dfrac{8}{14}\)\(=\dfrac{8:2}{14:2}=\dfrac{4}{7}\) , \(\dfrac{18}{-60}=\dfrac{18:6}{-60:6}=\dfrac{3}{-10}=\dfrac{-3}{10}\)
\(\dfrac{-270}{360}=\dfrac{-270:90}{360:90}=\dfrac{-3}{4}\)
\(c,\dfrac{3.4+3.7}{6.5+9}\) = \(\dfrac{3.\left(4+7\right)}{30+9}\) = \(\dfrac{3.11}{39}\) = \(\dfrac{3.11}{3.13}=\dfrac{11}{13}\)
\(\dfrac{-63}{81},\dfrac{9.6}{9.35},\dfrac{7.2+8}{2.14.5}\)
Các p/s đã tối giản : ko có
\(\dfrac{-63}{81}=\dfrac{-63:9}{81:9}=\dfrac{-7}{9}\) , \(\dfrac{9.6}{9.35}=\dfrac{6}{35}\)
\(\dfrac{7.2+8}{2.14.5}=\dfrac{14+8}{28.5}=\dfrac{22}{140}=\dfrac{11}{70}\)
a) \(\dfrac{11}{21}+\dfrac{-4}{7}=\dfrac{11}{21}+\dfrac{-12}{21}=\dfrac{-1}{21}\)
b) \(\dfrac{5}{15}+\dfrac{14}{25}-\dfrac{12}{9}+\dfrac{2}{7}+\dfrac{11}{25}=\dfrac{1}{3}+\dfrac{14}{25}-\dfrac{4}{3}+\dfrac{2}{7}+\dfrac{11}{25}\)
\(=\left(\dfrac{1}{3}-\dfrac{4}{3}\right)+\left(\dfrac{14}{25}+\dfrac{11}{25}\right)+\dfrac{2}{7}=-1+1+\dfrac{2}{7}=\dfrac{2}{7}\)
c) \(\dfrac{2}{3}+\dfrac{5}{7}-\dfrac{3}{14}=\dfrac{28}{42}+\dfrac{30}{42}-\dfrac{9}{42}=\dfrac{49}{42}=\dfrac{7}{6}\)
d) \(\dfrac{2}{5}-\dfrac{3}{7}+\dfrac{9}{45}=\dfrac{2}{5}-\dfrac{3}{7}+\dfrac{1}{5}=\dfrac{14}{35}-\dfrac{15}{35}+\dfrac{7}{35}=\dfrac{6}{35}\)
e) \(\dfrac{21}{47}+\dfrac{9}{45}+\dfrac{26}{47}+\dfrac{45}{5}=\dfrac{21}{47}+\dfrac{1}{5}+\dfrac{26}{47}+\dfrac{45}{5}=\left(\dfrac{21}{47}+\dfrac{26}{47}\right)+\left(\dfrac{1}{5}+\dfrac{45}{5}\right)\)
\(=1+\dfrac{46}{5}=\dfrac{51}{5}\)
f) \(\dfrac{15}{12}-\dfrac{18}{13}+\dfrac{5}{13}-\dfrac{3}{12}=\left(\dfrac{15}{12}-\dfrac{3}{12}\right)+\left(-\dfrac{18}{13}+\dfrac{5}{13}\right)=1+\left(-1\right)=0\)
g) \(\dfrac{-8}{18}-\dfrac{15}{27}=\dfrac{-4}{9}-\dfrac{5}{9}=\dfrac{-9}{9}=-1\)
h)\(\dfrac{3}{7}+\dfrac{-5}{2}-\dfrac{3}{5}=\dfrac{30}{70}+\dfrac{-175}{70}-\dfrac{42}{70}=\dfrac{-187}{70}\)
i) \(\left(\dfrac{11}{12}:\dfrac{33}{16}\right).\dfrac{3}{5}=\dfrac{11}{12}.\dfrac{16}{33}.\dfrac{3}{5}=\dfrac{11.16.3}{12.33.5}=\dfrac{4}{15}\)
Các bạn ơi,mình ghi thiếu,còn 3 câu nữa nha!!!~~nya
e)| \(\dfrac{5}{2}\)x-\(\dfrac{1}{2}\) |-(-22).\(\dfrac{1}{3}\)(0,75-\(\dfrac{1}{7}\))=\(\dfrac{-5}{13}\):2\(\dfrac{9}{13}\)-0,5.(\(\dfrac{-2}{3}\))
f)| 5x+21 | = | 2x -63 |
g) -45 - |-3x-96 | - 54=-207
Làm ơn giúp mình với ạ!Mình đang cần gấp lắm trong ngày hôm nay ạ!!!Mình xin cảm ơn các bạn nhiều nhiều lắm luôn đó!!!Thank you very much!!!(^-^)
a, (\(\dfrac{2}{9}\)(6x - \(\dfrac{3}{4}\)) - 3(\(\dfrac{1}{4}x-\dfrac{1}{5}\)) = \(\dfrac{-8}{15}\)
<=> (\(\dfrac{4}{3}x-\dfrac{1}{6}\)) - (\(\dfrac{3}{4}x-\dfrac{3}{5}\)) = \(\dfrac{-8}{15}\)
<=> \(\dfrac{4}{3}x-\dfrac{1}{6}-\dfrac{3}{4}x+\dfrac{3}{5}=\dfrac{-8}{15}\)
<=> \(\dfrac{7}{12}x+\dfrac{13}{30}=\dfrac{-8}{15}\)
<=> \(\dfrac{7}{12}x=\dfrac{-8}{15}-\dfrac{13}{30}\)
<=> \(\dfrac{7}{12}x=-\dfrac{29}{30}\)
<=> x = \(-\dfrac{58}{35}\)
@Nguyễn Gia Hân
\(a.8,2+\left(-3,5\right)+50+3,5+\left(-8,2\right)\\ =\left(8,2-8,2\right)+\left(3,5-3,5\right)+50\\ =0+0+50\\ =50\\ b.\dfrac{8}{15}\cdot\dfrac{-45}{4}\\ =\dfrac{4\cdot2}{15}\cdot\dfrac{15\cdot-3}{4}\\ =2\cdot-3\\ =-6\)
a: \(8,2+\left(-3,5\right)+50+3,5+\left(-8,2\right)\)
\(=\left(8,2-8,2\right)+\left(3,5-3,5\right)+50\)
=0+0+50
=50
b: \(\dfrac{8}{15}\cdot\dfrac{-45}{4}=\dfrac{8}{4}\cdot\dfrac{-45}{15}=2\cdot\left(-3\right)=-6\)