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14 tháng 4 2023

   5\(\dfrac{2}{7}\) - ( 3\(\dfrac{1}{5}\) + 2\(\dfrac{2}{7}\))

= 5 + \(\dfrac{2}{7}\) - ( 3 + \(\dfrac{1}{5}\) + 2 + \(\dfrac{2}{7}\))

= 5 + \(\dfrac{2}{7}\) - 3 - \(\dfrac{1}{5}\) - 2 - \(\dfrac{2}{7}\)

= ( 5 - 3 - 2) + ( \(\dfrac{2}{7}\) - \(\dfrac{2}{7}\)) - \(\dfrac{1}{5}\)

= ( 5 - 5) + 0  - \(\dfrac{1}{5}\)

= 0 + 0 - \(\dfrac{1}{5}\)

= - \(\dfrac{1}{5}\)

14 tháng 4 2023

\(5\dfrac{2}{7}-3\dfrac{1}{5}-2\dfrac{2}{7}\\ 5\dfrac{2}{7}-2\dfrac{2}{7}-3\dfrac{1}{5}\\ 3\dfrac{2}{7}-3\dfrac{1}{5}\\ \dfrac{2}{7}-\dfrac{1}{5}\\ \dfrac{10}{35}-\dfrac{7}{35}\\ \dfrac{3}{35}\)

25 tháng 4 2022

\(49,=\dfrac{38}{5}-\left(\dfrac{19}{7}+\dfrac{28}{5}\right)\)

\(=\dfrac{38}{5}-\dfrac{19}{7}-\dfrac{28}{5}\)

\(=\left(\dfrac{38}{5}-\dfrac{28}{5}\right)-\dfrac{19}{7}\)

\(=2-\dfrac{19}{7}=-\dfrac{5}{7}\)

\(50,=\dfrac{25}{81}.\dfrac{15}{22}=\dfrac{125}{594}\)

mik xinloi ạ câu 50 mik viết sai đề nên mong bạn giải lại giúp ạ <3

23 tháng 8 2023

\(=\left(-\dfrac{3}{4}+\dfrac{5}{13}\right).\dfrac{7}{2}-\left(\dfrac{9}{4}+\dfrac{8}{13}\right).\dfrac{7}{2}\\ =\dfrac{7}{2}\left(-\dfrac{3}{4}+\dfrac{5}{13}-\dfrac{9}{4}-\dfrac{8}{13}\right)\\ =\dfrac{7}{2}\left(-\dfrac{12}{4}-\dfrac{3}{13}\right)\\ =\dfrac{7}{2}\left(-3-\dfrac{3}{13}\right)\\ =\dfrac{7}{2}\left(-\dfrac{39}{13}-\dfrac{3}{13}\right)\\ =\dfrac{7}{2}\left(-\dfrac{42}{13}\right)\\ =\dfrac{7.\left(-42\right)}{2.13}\\ =-\dfrac{147}{13}\)

15 tháng 12 2021

\(a.=\dfrac{1}{2}-\dfrac{1}{3}-\dfrac{5}{3}+\dfrac{3}{2}+\dfrac{7}{3}-\dfrac{5}{2}=\dfrac{1+3-5}{2}-\dfrac{2+5-7}{3}=\dfrac{-1}{2}\)

\(b.\left(\dfrac{3}{4}-1\dfrac{1}{6}\right)^2:\sqrt{\dfrac{25}{144}}=\left(-\dfrac{5}{12}\right)^2:\dfrac{5}{12}=\dfrac{5}{12}\)

15 tháng 12 2021

thanks nhìu

AH
Akai Haruma
Giáo viên
25 tháng 7 2021

Bài 1:

a.

$|x+\frac{7}{4}|=\frac{1}{2}$

\(\Leftrightarrow \left[\begin{matrix} x+\frac{7}{4}=\frac{1}{2}\\ x+\frac{7}{4}=-\frac{1}{2}\end{matrix}\right.\Leftrightarrow \left[\begin{matrix} x=\frac{-5}{4}\\ x=\frac{-9}{4}\end{matrix}\right.\)

b. $|2x+1|-\frac{2}{5}=\frac{1}{3}$
$|2x+1|=\frac{1}{3}+\frac{2}{5}$

$|2x+1|=\frac{11}{15}$

\(\Leftrightarrow \left[\begin{matrix} 2x+1=\frac{11}{15}\\ 2x+1=\frac{-11}{15}\end{matrix}\right.\Leftrightarrow \left[\begin{matrix} x=\frac{-2}{15}\\ x=\frac{-13}{15}\end{matrix}\right.\)

c.

$3x(x+\frac{2}{3})=0$

\(\Leftrightarrow \left[\begin{matrix} 3x=0\\ x+\frac{2}{3}=0\end{matrix}\right.\Leftrightarrow \left[\begin{matrix} x=0\\ x=\frac{-3}{2}\end{matrix}\right.\)

d.

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

$\Leftrightarrow x=\frac{2}{5}$

AH
Akai Haruma
Giáo viên
25 tháng 7 2021

Nguyễn Quý Trung:

\(x+\dfrac{1}{3}=\dfrac{2}{5}+\dfrac{1}{3}\)

Bạn bớt 2 vế đi 1/3 thì \(x=\dfrac{2}{5}\)

23 tháng 1 2022

\(\left|\dfrac{1}{2}+\dfrac{-2}{3}\right|.\dfrac{24}{7}-\dfrac{4}{7}.\dfrac{3}{5}+\dfrac{2}{5}.\left(\dfrac{-4}{7}\right)\)

\(=\left|-\dfrac{1}{6}\right|.\dfrac{24}{7}+\left(-\dfrac{4}{7}\right).\dfrac{3}{5}+\dfrac{2}{5}.\left(\dfrac{-4}{7}\right)\)

\(=\dfrac{1}{6}.\dfrac{24}{7}+\left(-\dfrac{4}{7}\right).\left(\dfrac{3}{5}+\dfrac{2}{5}\right)\)

\(=\dfrac{4}{7}-\dfrac{4}{7}.1\)

\(=\dfrac{4}{7}-\dfrac{4}{7}\\ =0\)

 

23 tháng 1 2022

thank you a ILoveMath 

a: =9+7=16

b: =11+3/13-2-4/7-5-3/13

=4-4/7

=28/7-4/7=24/7

c: =2/7(5+1/4-3-1/4)=2/7x2=4/7

10 tháng 3 2022

\(2\dfrac{1}{3}.3=\dfrac{7}{3}.3=7.\\ \left(\dfrac{2}{5}-\dfrac{3}{4}\right)-\dfrac{2}{5}=\dfrac{2}{5}-\dfrac{3}{4}-\dfrac{2}{5}=-\dfrac{3}{4}.\\ \dfrac{-10}{11}.\dfrac{4}{7}+\dfrac{-10}{11}.\dfrac{3}{7}+1\dfrac{10}{11}.\\ =\dfrac{-10}{11}\left(\dfrac{4}{7}+\dfrac{3}{7}-1\right).\\ =\dfrac{-10}{11}.\left(1-1\right)=0.\)

10 tháng 3 2022

1) 2\(\dfrac{1}{3}\).3=\(\dfrac{7}{3}\).3=7.

2) (2/5 -3/4) -2/5 = 2/5 -3/4 -2/5 = -3/4.

3) \(\dfrac{-10}{11}.\dfrac{4}{7}+\dfrac{-10}{11}.\dfrac{3}{7}+1\dfrac{10}{11}=\dfrac{1}{11}\left(-\dfrac{40}{7}-\dfrac{30}{7}+21\right)=\dfrac{1}{11}.\left(-10+21\right)=1\).

22 tháng 3 2017

11) \(\dfrac{5}{7}\left(\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{4}{7}\right)+\left(\dfrac{1}{3}-\dfrac{1}{2}-\dfrac{4}{7}\right):\dfrac{7}{5}\)

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

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

= \(\dfrac{5}{7}\cdot0\)

=0

12) \(\dfrac{43}{5}\left(\dfrac{17}{3}-\dfrac{16}{9}+2\right)-\dfrac{43}{5}\left(\dfrac{17}{3}-\dfrac{16}{9}\right)\)

= \(\dfrac{43}{5}\left(\dfrac{17}{3}-\dfrac{16}{9}+2-\dfrac{17}{3}+\dfrac{16}{9}\right)\)

= \(\dfrac{43}{5}\cdot2=\dfrac{43}{10}\)

25 tháng 7 2017

11, 5/7( 1/2-1/3+1/4)+ (1/3-1/2-1/4):7/5

= 5/7.(1/2 - 1/3 + 1/4 )+( 1/3 - 1/2 - 1/4). 5/7

= 5/7.(1/2 - 2/3 + 1/4 + 1/3 - 1/2 - 1/4)

= 5/7 . -1/3

= -5/21

12, 43/5.(17/3 - 16/9 + 2)- 43/5. (17/3 - 16/9)

= 43/5.( 17/3 - 16/9 + 2 - 17/3 + 16/9)

= 43/5 . 2

= 86/5