\(\frac{1^2}{2^2}\)+\(\frac{25}{3}\).
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18 tháng 10 2018

\(3\frac{1}{2}-\frac{1}{2}.\left(-4,25-\frac{3}{4}\right)^2:\frac{5}{4}\)

\(=\frac{7}{2}-\frac{1}{2}.\left(-4,25-0,75\right)^2:\frac{5}{4}\)

\(=\frac{7}{2}-\frac{1}{2}.\left(-5\right)^2:\frac{5}{4}\)

\(=\frac{7}{2}-\frac{1}{2}.5.\frac{4}{5}\)

\(=\frac{7}{2}-2\)

\(=\frac{7}{2}-\frac{4}{2}\)

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

\(\frac{3}{7}.1\frac{1}{2}+\frac{3}{7}.0,5-\frac{3}{7}.9\)

\(=\frac{3}{7}.\left(\frac{3}{2}+\frac{1}{2}-9\right)\)

\(=\frac{3}{7}.\left(2-9\right)\)

\(=\frac{3}{7}.\left(-7\right)\)

\(=-3\)

\(\frac{125^{2016}.8^{2017}}{50^{2017}.20^{2018}}=\frac{\left(5^3\right)^{2016}.\left(2^3\right)^{2017}}{\left(5^2\right)^{2017}.2^{2017}.\left(2^2\right)^{2018}.5^{2018}}=\frac{\left(5^3\right)^{2016}.\left(2^3\right)^{2017}}{\left(5^3\right)^{2017}.\left(2^3\right)^{2017}.2.5}=\frac{1}{5^4.2}=\frac{1}{1250}\)( tính nhẩm, ko chắc đúng )

18 tháng 10 2018

a) \(3\frac{1}{2}-\frac{1}{2}\cdot\left(-4,25-\frac{3}{4}\right)^2\) : \(\frac{5}{4}\)

\(3\cdot25:\frac{5}{4}\)

\(3\cdot\left(25:\frac{5}{4}\right)\)

=\(3\cdot20\)

=60

b)=\(\frac{3}{7}\cdot\left(1\frac{1}{2}+0,5-9\right)\)

=\(\frac{3}{7}\cdot\left(-7\right)\)

=\(-3\)

c) = 

1) Tính: 1. (-3)2 . (\(\frac{3}{4}\) - 0,25) - (3\(\frac{1}{2}\) - 1\(\frac{1}{2}\)) 2. \(\frac{13}{25}\) + \(\frac{6}{41}\) - \(\frac{38}{25}\) + \(\frac{35}{41}\) - \(\frac{1}{2}\) 3. \(\frac{1}{2}\).\(\sqrt{64}\) - \(\sqrt{\frac{4}{25}}\) + (-1)2007 4. (-\(\frac{5}{2}\))2 : (-15) - (-0,45 + \(\frac{3}{4}\)) . (-1\(\frac{5}{9}\)) 5. E = \(\frac{4^5.9^4-2.6^9}{2^{10}.3^8+6^8.20}\) \(\frac{5^4.20^4}{25^5.4^5}\) 2) Tìm x: 1. 3,2x + (-1,2)x +2,7 = -4,9 2. (giá trị tuyệt đói...
Đọc tiếp

1) Tính:

1. (-3)2 . (\(\frac{3}{4}\) - 0,25) - (3\(\frac{1}{2}\) - 1\(\frac{1}{2}\))

2. \(\frac{13}{25}\) + \(\frac{6}{41}\) - \(\frac{38}{25}\) + \(\frac{35}{41}\) - \(\frac{1}{2}\)

3. \(\frac{1}{2}\).\(\sqrt{64}\) - \(\sqrt{\frac{4}{25}}\) + (-1)2007

4. (-\(\frac{5}{2}\))2 : (-15) - (-0,45 + \(\frac{3}{4}\)) . (-1\(\frac{5}{9}\))

5. E = \(\frac{4^5.9^4-2.6^9}{2^{10}.3^8+6^8.20}\)

\(\frac{5^4.20^4}{25^5.4^5}\)

2) Tìm x:

1. 3,2x + (-1,2)x +2,7 = -4,9

2. (giá trị tuyệt đói của x) - 2,2 = 1,3

3. (giá trị tuyệt đối của x + \(\frac{3}{4}\)) - \(\frac{1}{3}\) = 0

4. (giá trị tuyệt đối của x - 1,5) + (giá trị tuyệt đối của 2,5 - x) = 0

5. \(\frac{3}{4}\) : \(\frac{41}{99}\) = x : \(\frac{75}{90}\); 0,4 : x = x : 0,9

6. (2x + 3 )2 = 25

7. (\(\frac{2}{3}\)x -1)(\(\frac{3}{4}\)x + \(\frac{1}{2}\)) = 0

8. x : \(\frac{9}{14}\) = \(\frac{7}{3}\) : x

9. (x - \(\frac{1}{2}\))3 = \(\frac{1}{27}\)

10. (-\(\frac{2}{3}\))2 . x = (-\(\frac{2}{3}\))5

11. \(\frac{37-x}{x+13}\) = \(\frac{3}{7}\)

12. \(\frac{x}{-15}\) = \(\frac{-60}{x}\)

13. \(\frac{-2}{x}\) = \(\frac{-x}{\frac{8}{25}}\)

3) Tìm x, y, z biết:

1. \(\frac{x}{15}\) = \(\frac{y}{20}\) = \(\frac{z}{28}\) và 2x + 3y - 2 = 186

2. 2x = 3y; 5x = 7z và 3x - 7y + 5z = 30

3. \(\frac{x^2}{9}\) = \(\frac{y^2}{16}\) và x2 + y2 = 100

7
23 tháng 12 2019

lol

25 tháng 12 2019
3.1.\(\frac{x}{15}\)=\(\frac{y}{20}\)=\(\frac{z}{28}\)=\(\frac{2x}{30}\)=\(\frac{3y}{60}\)=\(\frac{2x+3y-z}{30+60-28}\)=\(\frac{186}{62}\)=3
=> x=3*15=45
y=3*20=60
z=3*28=84
24 tháng 4 2020

1.a) Sửa lại đề: \(\frac{11}{17}\)ở mẫu chuyển thành \(\frac{11}{7}\)

\(\frac{0,75+0,6-\frac{3}{7}-\frac{3}{13}}{2,75+2,2-\frac{11}{7}-\frac{11}{13}}=\frac{\frac{3}{4}+\frac{3}{5}-\frac{3}{7}-\frac{3}{13}}{\frac{11}{4}+\frac{11}{5}-\frac{11}{7}-\frac{11}{13}}\)\(=\frac{3\left(\frac{1}{4}+\frac{1}{5}-\frac{1}{7}-\frac{1}{13}\right)}{11\left(\frac{1}{4}+\frac{1}{5}-\frac{1}{7}-\frac{1}{13}\right)}=\frac{3}{11}\)

( vì \(\frac{1}{4}+\frac{1}{5}-\frac{1}{7}-\frac{1}{13}\ne0\))

2.a) \(\frac{3}{5}+\frac{3}{2}.x=\frac{-5}{7}\)\(\Leftrightarrow\frac{3}{2}.x=\frac{-5}{7}-\frac{3}{5}\)

\(\Leftrightarrow\frac{3}{2}.x=\frac{-46}{35}\)\(\Leftrightarrow x=\frac{-46}{35}:\frac{3}{2}\)\(\Leftrightarrow x=\frac{-92}{105}\)

Vậy \(x=\frac{-92}{105}\)

b) \(\left(4x-\frac{1}{3}\right).\left(\frac{3}{2}x+\frac{5}{6}\right)=0\)\(\Leftrightarrow\orbr{\begin{cases}4x-\frac{1}{3}=0\\\frac{3}{2}x+\frac{5}{6}=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}4x=\frac{1}{3}\\\frac{3}{2}x=\frac{-5}{6}\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\frac{1}{12}\\x=\frac{-5}{9}\end{cases}}\)

Vậy \(x=\frac{-5}{9}\)hoặc \(x=\frac{1}{12}\)

10 tháng 9 2020

giúp mik vs, mik bik các pạn giờ này đang ngủ rùi nhưng giúp mik lần này thui.yêu các pạn nhìu

12 tháng 9 2020

\(5\frac{1}{2}+\left(-3\right)=\frac{11}{2}+\frac{-3}{1}\)\(=\frac{11}{2}+\frac{-6}{2}=\frac{5}{2}\)\(;\)

\(4\frac{9}{11}+\left(-2\frac{1}{11}\right)=\frac{53}{11}+\frac{-23}{11}\)\(=\frac{30}{11}\)\(;\)

\(2\frac{1}{2}+\left(-6\right)=\frac{5}{2}+\frac{-6}{1}\)\(=\frac{5}{2}+\frac{-12}{2}=\frac{-7}{2}\)\(;\)

\(\left(-\frac{4}{5}\right)+\frac{1}{2}=\frac{-4}{5}+\frac{1}{2}\)\(=\frac{-8}{10}+\frac{5}{10}=\frac{-3}{10}\)\(;\)

\(4,3-\left(-1,2\right)=4,3+1,2=5,5\)\(=\frac{55}{10}=\frac{11}{2}\)\(;\)

\(0-\left(-0,4\right)=0+0,4=0,4\)\(=\frac{4}{10}=\frac{2}{5}\)\(;\)

\(\frac{-2}{3}-\frac{-1}{3}=\frac{-2}{3}+\frac{1}{3}=\frac{-1}{3}\)\(;\)

\(\frac{-1}{2}-\frac{-1}{6}=\frac{-1}{2}+\frac{1}{6}\)\(=\frac{-3}{6}+\frac{1}{6}=\frac{-2}{6}=\frac{-1}{3}\)\(;\)

\(x+\frac{1}{3}=\frac{3}{4}\)                                \(;\)               \(x-\frac{2}{5}=\frac{5}{7}\)            \(;\)      

    \(x=\frac{3}{4}-\frac{1}{3}\)                                                             \(x=\frac{5}{7}+\frac{2}{5}\)

    \(x=\frac{5}{12}\)                                                                        \(x=\frac{39}{35}\)

\(-x-\frac{2}{3}=-\frac{6}{7}\)                                \(;\)               \(\frac{4}{7}-x=\frac{1}{3}\)

 \(\frac{6}{7}-\frac{2}{3}=x\)                                                          \(\frac{4}{7}-\frac{1}{3}=x\)

            \(\frac{4}{21}=x\) \(\Leftrightarrow\)\(x=\frac{4}{21}\)                                                       \(\frac{5}{21}=x\)\(\Leftrightarrow\)\(x=\frac{5}{12}\)

21 tháng 9 2018

\(\frac{1}{2}+\frac{2}{3}-\frac{3}{4}+\frac{4}{5}-\frac{5}{6}+\frac{6}{7}+\frac{5}{6}-\frac{4}{5}+\frac{3}{4}-\frac{2}{3}+\frac{1}{2}\)

\(=\left(\frac{1}{2}+\frac{1}{2}+\frac{6}{7}\right)+\left(\frac{2}{3}-\frac{2}{3}\right)+\left(\frac{-3}{4}+\frac{3}{4}\right)+\left(\frac{4}{5}-\frac{4}{5}\right)+\left(\frac{-5}{6}+\frac{5}{6}\right)\)

\(=\frac{13}{7}+0+0+0+0\)

\(=\frac{13}{7}\)

21 tháng 9 2018

\(\frac{1}{2}+\frac{2}{3}-\frac{3}{4}+\frac{4}{5}-\frac{5}{6}+\frac{6}{7}+\frac{5}{6}-\frac{4}{5}+\frac{3}{4}-\frac{2}{3}+\frac{1}{2}.\)

\(=\left(\frac{1}{2}+\frac{1}{2}\right)+\left(\frac{2}{3}-\frac{2}{3}\right)-\left(\frac{3}{4}-\frac{3}{4}\right)+\left(\frac{4}{5}-\frac{4}{5}\right)-\left(\frac{5}{6}-\frac{5}{6}\right)+\frac{6}{7}\)

\(=1+0-0+0+\frac{6}{7}\)

\(=1+\frac{6}{7}=1\frac{6}{7}\)