1.Tìm x, biết:a.$\frac{1}{2}$x$x$ $\frac{2}{3}$=$\frac{5}{2}$b.$\frac{x}{12}$ $\frac{5}{24}$=$\frac{5}{6}$c.(1234 $x$ 766)x0,25=6,2:0,012.Tính bằng cách hợp lý.A=$\frac{1}{2}$x\(\fra...

1.Tìm x, biết:a.$\frac{1}{2}$x$x$+$\frac{2}{3}$=$\frac{5}{2}$b.$\frac{x}{12}$+$\frac{5}{24}$=$\frac{5}{6}$c.(1234+$x$+766)x0,25=6,2:0,012.Tính bằng cách hợp...

#Toán lớp 5

0

NV

Nguyễn Văn Đức

8 tháng 8 2016

#Toán lớp 5

0

QT

Quoc Tran Anh Le

Giáo viên

19 tháng 9 2023

Tìm x, biết:

a)$x.\frac{{14}}{{27}} = \frac{{ - 7}}{9}$

b)$\left( {\frac{{ - 5}}{9}} \right):x = \frac{2}{3};$

c)$\frac{2}{5}:x = \frac{1}{{16}}:0,125$

d)$ - \frac{5}{{12}}x = \frac{2}{3} - \frac{1}{2}$

1

HQ

Hà Quang Minh

Giáo viên

19 tháng 9 2023

a)

$\begin{array}{l}x.\frac{{14}}{{27}} = \frac{{ - 7}}{9}\\x = \frac{{ - 7}}{9}:\frac{{14}}{{27}}\\x = \frac{{ - 7}}{9}.\frac{{27}}{{14}}\\x = \frac{{ - 3}}{2}\end{array}$

Vậy $x = \frac{{ - 3}}{2}$.

b)

$\begin{array}{l}\left( {\frac{{ - 5}}{9}} \right):x = \frac{2}{3}\\x = \left( {\frac{{ - 5}}{9}} \right):\frac{2}{3}\\x = \left( {\frac{{ - 5}}{9}} \right).\frac{3}{2}\\x = \frac{{ - 5}}{6}\end{array}$

Vậy $x = \frac{{ - 5}}{6}$.

c)

$\begin{array}{l}\frac{2}{5}:x = \frac{1}{{16}}:0,125\\\frac{2}{5}:x = \frac{1}{{16}}:\frac{1}{8}\\\frac{2}{5}:x = \frac{1}{{16}}.8\\\frac{2}{5}:x = \frac{1}{2}\\x = \frac{2}{5}:\frac{1}{2}\\x = \frac{2}{5}.2\\x = \frac{4}{5}\end{array}$

Vậy $x = \frac{4}{5}$

d)

$\begin{array}{l} - \frac{5}{{12}}x = \frac{2}{3} - \frac{1}{2}\\ - \frac{5}{{12}}x = \frac{4}{6} - \frac{3}{6}\\ - \frac{5}{{12}}x = \frac{1}{6}\\x = \frac{1}{6}:\left( { - \frac{5}{{12}}} \right)\\x = \frac{1}{6}.\frac{{ - 12}}{5}\\x = \frac{{ - 2}}{5}\end{array}$

Vậy $x = \frac{{ - 2}}{5}$.

Chú ý: Khi trình bày lời giải bài tìm x, sau khi tính xong, ta phải kết luận.

QT

Quoc Tran Anh Le

Giáo viên

19 tháng 9 2023

Tìm x, biết:

a)$\frac{2}{9}:x + \frac{5}{6} = 0,5;$

b)$\frac{3}{4} - \left( {x - \frac{2}{3}} \right) = 1\frac{1}{3};$

c)$1\frac{1}{4}:\left( {x - \frac{2}{3}} \right) = 0,75;$

d)$\left( { - \frac{5}{6}x + \frac{5}{4}} \right):\frac{3}{2} = \frac{4}{3}$.

1

HQ

Hà Quang Minh

Giáo viên

19 tháng 9 2023

a)

$\begin{array}{l}\frac{2}{9}:x + \frac{5}{6} = 0,5\\\frac{2}{9}:x = \frac{1}{2} - \frac{5}{6}\\\frac{2}{9}:x = \frac{3}{6} - \frac{5}{6}\\\frac{2}{9}:x = \frac{{ - 2}}{6}\\x = \frac{2}{9}:\frac{{ - 2}}{6}\\x = \frac{2}{9}.\frac{{ - 6}}{2}\\x = \frac{{ - 2}}{3}\end{array}$

Vậy $x = \frac{{ - 2}}{3}$.

b)

$\begin{array}{l}\frac{3}{4} - \left( {x - \frac{2}{3}} \right) = 1\frac{1}{3}\\x - \frac{2}{3} = \frac{3}{4} - 1\frac{1}{3}\\x - \frac{2}{3} = \frac{3}{4} - \frac{4}{3}\\x - \frac{2}{3} = \frac{9}{{12}} - \frac{{16}}{{12}}\\x - \frac{2}{3} = \frac{{ - 7}}{{12}}\\x = \frac{{ - 7}}{{12}} + \frac{2}{3}\\x = \frac{{ - 7}}{{12}} + \frac{8}{{12}}\\x = \frac{1}{12}\end{array}$

Vậy$x = \frac{1}{12}$.

c)

$\begin{array}{l}1\frac{1}{4}:\left( {x - \frac{2}{3}} \right) = 0,75\\\frac{5}{4}:\left( {x - \frac{2}{3}} \right) = \frac{3}{4}\\x - \frac{2}{3} = \frac{5}{4}:\frac{3}{4}\\x - \frac{2}{3} = \frac{5}{4}.\frac{4}{3}\\x - \frac{2}{3} = \frac{5}{3}\\x = \frac{5}{3} + \frac{2}{3}\\x = \frac{7}{3}\end{array}$

Vậy $x = \frac{7}{3}$.

d)

$\begin{array}{l}\left( { - \frac{5}{6}x + \frac{5}{4}} \right):\frac{3}{2} = \frac{4}{3}\\ - \frac{5}{6}x + \frac{5}{4} = \frac{4}{3}.\frac{3}{2}\\ - \frac{5}{6}x + \frac{5}{4} = 2\\ - \frac{5}{6}x = 2 - \frac{5}{4}\\ - \frac{5}{6}x = \frac{8}{4} - \frac{5}{4}\\ - \frac{5}{6}x = \frac{3}{4}\\x = \frac{3}{4}:\left( { - \frac{5}{6}} \right)\\x = \frac{3}{4}.\frac{{ - 6}}{5}\\x = \frac{{ - 9}}{{10}}\end{array}$

Vậy $x = \frac{{ - 9}}{{10}}$.

H2

Hiếu 2k6

5 tháng 3 2020

Ai giúp vs !!!
$a.\frac{3x-7}{5}=\frac{2x-1}{3}\\ b.\frac{4x-7}{12}-x=\frac{3x}{8}\\ c.\frac{x-2009}{1234}+\frac{x-2009}{5678}-\frac{x-2009}{197}=0\\ d.\frac{5x-8}{3}=\frac{1-3x}{2}\\ e.\frac{x-5}{6}-\frac{x-9}{4}=\frac{5x-3}{8}+2\\ f.\frac{x-1}{\frac{2}{5}}-3-\frac{3x-2}{\frac{5}{4}}-2=1$

#Toán lớp 8

8

KN

Kiệt Nguyễn

5 tháng 3 2020

$\frac{3x-7}{5}=\frac{2x-1}{3}$

$\Leftrightarrow9x-21=10x-5$

$\Leftrightarrow-x=16\Leftrightarrow x=-16$

$\frac{4x-7}{12}-x=\frac{3x}{8}$

$\Leftrightarrow\frac{4x-7-12x}{12}=\frac{3x}{8}$

$\Leftrightarrow\frac{-7-8x}{12}=\frac{3x}{8}$

$\Leftrightarrow-56-64x=36x$

$\Leftrightarrow-56=100x\Leftrightarrow x=\frac{-14}{25}$

KN

Kiệt Nguyễn

5 tháng 3 2020

$\frac{x-2009}{1234}+\frac{x-2009}{5678}-\frac{x-2009}{197}=0$

$\Leftrightarrow\left(x-2019\right)\left(\frac{1}{1234}+\frac{1}{5678}-\frac{1}{197}\right)=0$

Vì $\left(\frac{1}{1234}+\frac{1}{5678}-\frac{1}{197}\right)\ne0$nên x - 2019 = 0

Vậy x = 2019

$\frac{5x-8}{3}=\frac{1-3x}{2}$

$\Leftrightarrow10x-16=3-9x$

$\Leftrightarrow19x=19\Leftrightarrow x=1$

bài 1 tính bằng cách hợp lí nếu có thể$\frac{-5}{12}$-$\frac{-3}{24}$=b) 5$\frac{5}{13}$-(1$\frac{1}{2}+3\frac{5}{13}$)c)$\frac{-13}{37}.\frac{5}{23}+\frac{-13}{37}.\frac{18}{23}+\frac{50}{37}$d)(0,5 -$\frac{3}{2}$):1$\frac{1}{6}+75\%$bài 2 tìm x biết-7/5 +x = -3/4-7/4 + 1/4 : x =...

L

linh

27 tháng 3 2018

#Toán lớp 6

0

QT

Quoc Tran Anh Le

Giáo viên

19 tháng 9 2023

Tìm x, biết:

a)$x:{\left( {\frac{{ - 1}}{2}} \right)^3} = - \frac{1}{2};$ b)$x.{\left( {\frac{3}{5}} \right)^7} = {\left( {\frac{3}{5}} \right)^9};$

c)${\left( {\frac{{ - 2}}{3}} \right)^{11}}:x = {\left( {\frac{{ - 2}}{3}} \right)^9};$ d)$x.{\left( {0,25} \right)^6} = {\left( {\frac{1}{4}} \right)^8}$

1

HQ

Hà Quang Minh

Giáo viên

19 tháng 9 2023

a)

$\begin{array}{l}x:{\left( {\frac{{ - 1}}{2}} \right)^3} = - \frac{1}{2}\\x = - \frac{1}{2}.{\left( {\frac{{ - 1}}{2}} \right)^3}\\x = {\left( {\frac{{ - 1}}{2}} \right)^4}\\x = \frac{1}{{16}}\end{array}$

Vậy $x = \frac{1}{{16}}$.

b)

$\begin{array}{l}x.{\left( {\frac{3}{5}} \right)^7} = {\left( {\frac{3}{5}} \right)^9}\\x = {\left( {\frac{3}{5}} \right)^9}:{\left( {\frac{3}{5}} \right)^7}\\x = {\left( {\frac{3}{5}} \right)^2}\\x = \frac{9}{{25}}\end{array}$

Vậy $x = \frac{9}{{25}}$.

c)

$\begin{array}{l}{\left( {\frac{{ - 2}}{3}} \right)^{11}}:x = {\left( {\frac{{ - 2}}{3}} \right)^9}\\x = {\left( {\frac{{ - 2}}{3}} \right)^{11}}:{\left( {\frac{{ - 2}}{3}} \right)^9}\\x = {\left( {\frac{{ - 2}}{3}} \right)^2}\\x = \frac{4}{9}.\end{array}$

Vậy $x = \frac{4}{9}$.

d)

$\begin{array}{l}x.{\left( {0,25} \right)^6} = {\left( {\frac{1}{4}} \right)^8}\\x.{\left( {\frac{1}{4}} \right)^6} = {\left( {\frac{1}{4}} \right)^8}\\x = {\left( {\frac{1}{4}} \right)^8}:{\left( {\frac{1}{4}} \right)^6}\\x = {\left( {\frac{1}{4}} \right)^2}\\x = \frac{1}{{16}}\end{array}$

Vậy $x = \frac{1}{{16}}$.

QT

Quoc Tran Anh Le

Giáo viên

16 tháng 9 2023

Tìm x, biết:

a)$x + \left( { - \frac{1}{5}} \right) = \frac{{ - 4}}{{15}}$;

b)$3,7 - x = \frac{7}{{10}};$

c)$x.\frac{3}{2} = 2,4$;

d)$3,2:x = - \frac{6}{{11}}$.

1

HQ

Hà Quang Minh

Giáo viên

16 tháng 9 2023

a)

$\begin{array}{l}x + \left( { - \frac{1}{5}} \right) = \frac{{ - 4}}{{15}}\\x = \frac{{ - 4}}{{15}} + \frac{1}{5}\\x = \frac{{ - 4}}{{15}} + \frac{3}{{15}}\\x = \frac{{ - 1}}{{15}}\end{array}$

Vậy $x = \frac{{ - 1}}{{15}}$.

b)

$\begin{array}{l}3,7 - x = \frac{7}{{10}}\\x = 3,7 - \frac{7}{{10}}\\x = \frac{{37}}{{10}} - \frac{7}{{10}}\\x=\frac{30}{10}\\x = 3\end{array}$

Vậy $x = 3$.

c)

$\begin{array}{l}x.\frac{3}{2} = 2,4\\x.\frac{3}{2} = \frac{{12}}{5}\\x = \frac{{12}}{5}:\frac{3}{2}\\x = \frac{{12}}{5}.\frac{2}{3}\\x = \frac{8}{5}\end{array}$

Vậy $x = \frac{8}{5}$

d)

$\begin{array}{l}3,2:x = - \frac{6}{{11}}\\\frac{{16}}{5}:x = - \frac{6}{{11}}\\x = \frac{{16}}{5}:\left( { - \frac{6}{{11}}} \right)\\x = \frac{{16}}{5}.\frac{{ - 11}}{6}\\x = \frac{{ - 88}}{{15}}\end{array}$

Vậy $x = \frac{{ - 88}}{{15}}$.

1 tìm x biết ;a, 0-|x + 1| = 5 b, 2 - | $\frac{3}{4}$- x | = $\frac{7}{12}$c, 2 | $\frac{1}{2}$x - $\frac{1}{3}$| - $\frac{3}{2}$= $\frac{1}{4}$d, | x - $\frac{1}{3}$| = $\frac{5}{6}$e, $\frac{3}{4}$- 2 | 2x - $\frac{2}{3}$| =...

AS

★彡 A͛r͛a͛k͛i͛ S͛e͛i͛j͛u͛r͛o͛ 彡★

9 tháng 3 2017

1) $\frac{24}{-12}=\frac{x}{5}=\frac{-y}{3}$Tìm x và y

2) $\frac{1}{3}+\frac{-2}{5}+\frac{1}{6}+\frac{-5}{25}\le\frac{x}{10}< \frac{-3}{4}+\frac{4}{14}+\frac{-2}{8}+\frac{-3}{5}+\frac{5}{7}$Tìm x

3) $\frac{8.x+18}{2.x+6}$Tìm x

#Toán lớp 6

0

I

ImAmNoob!!!

18 tháng 4 2021