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câu trả lời đây
- (\(\frac{3}{5}x-0,75\)):\(\frac{3}{7}=\frac{14}{5}\)
- ( \(\frac{3}{5}x-\frac{75}{100}\))\(:\frac{3}{7}=\frac{14}{5}\)
- (\(\frac{3}{5}x-\frac{3}{4}\))\(:\frac{3}{7}=\frac{14}{5}\)
- bí rồi ai giúp mình giải thêm nhé
(3x/5 - 3/4):3/7 =14/5
(3x/5-3/4).7/3 =21x/15 - 21/12 = 14/5
21x =( 14/5 +21/12).15
21x = 273/4
x = 13/4
đã làm là đúng
x =
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a) 5( x + 7 ) - 10 = 23.5 b) 72 - 7( 13 - x ) = 14
5( x + 7 ) - 10 = 40 49 - 7( 13 - x ) = 14
5( x + 7 ) = 40 + 10 7( 13 - x ) = 49 - 14
5( x + 7 ) = 50 7( 13 - x ) = 35
x + 7 = 50 : 5 13 - x = 35 : 7
x + 7 = 10 13 - x = 5
x = 10 - 7 x = 13 - 5
x = 3 x = 8
c) 5x - 52 = 10 d) 9x - 2.32 = 34
5x - 25 = 10 9x - 2.9 = 81
5x = 10 + 25 9x - 18 = 81
5x = 35 9x = 81 + 18
x = 35 : 5 9x = 99
x = 7 x = 99 : 9
x = 11
~ Hok tốt ~ ( Giờ mik mới thấy bài của bạn ỌwỌ )
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a) Ta có: \(\dfrac{2}{3}x-1=\dfrac{3}{2}\)
\(\Leftrightarrow x\cdot\dfrac{2}{3}=\dfrac{5}{2}\)
hay \(x=\dfrac{5}{2}:\dfrac{2}{3}=\dfrac{5}{2}\cdot\dfrac{3}{2}=\dfrac{15}{4}\)
b) Ta có: \(\left|5x-\dfrac{1}{2}\right|-\dfrac{2}{7}=25\%\)
\(\Leftrightarrow\left|5x-\dfrac{1}{2}\right|=\dfrac{1}{4}+\dfrac{2}{7}=\dfrac{15}{28}\)
\(\Leftrightarrow\left[{}\begin{matrix}5x-\dfrac{1}{2}=\dfrac{15}{28}\\5x-\dfrac{1}{2}=\dfrac{-15}{28}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}5x=\dfrac{29}{28}\\5x=\dfrac{-1}{28}\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{29}{140}\\x=\dfrac{-1}{140}\end{matrix}\right.\)
c) Ta có: \(\dfrac{x-3}{4}=\dfrac{16}{x-3}\)
\(\Leftrightarrow\left(x-3\right)^2=64\)
\(\Leftrightarrow\left[{}\begin{matrix}x-3=8\\x-3=-8\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=11\\x=-5\end{matrix}\right.\)
d) Ta có: \(\dfrac{-8}{13}+\dfrac{7}{17}+\dfrac{21}{31}\le x\le\dfrac{-9}{14}+4-\dfrac{5}{14}\)
\(\Leftrightarrow\dfrac{3246}{6851}\le x\le3\)
\(\Leftrightarrow x\in\left\{1;2;3\right\}\)
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\(a,5x-5\left(-3\right)=15\)
\(\Leftrightarrow5x+15=15\)
\(\Leftrightarrow5x=0\)
\(\Leftrightarrow0\)
\(b,x=\frac{18.36.\left(-119\right)}{12.9.17}\)
\(=\frac{2.3^2.2^2.3^2.\left(-7\right).17}{2^2.3.17}\)
\(=\frac{-2^3.3^4.7.17}{2^2.3.17}\)
\(=-2.3^3.7\)
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Lời giải:
$7^{5x}:49=7^{28}$
$7^{5x}:7^2=7^{28}$
$7^{5x-2}=7^{28}$
$\Rightarrow 5x-2=28$
$\Rightarrow 5x=30$
$\Rightarrow x=6$
b.
$5^{2x}.5^{14}=5^{30}$
$5^{2x+14}=5^{30}$
$\Rightarrow 2x+14=30$
$\Rightarrow 2x=16$
$\Rightarrow x=8$
a) 7^5x:49=7^28
7^5x:7^2=7^28
7^5x=7^28.7^2
7^5x=7^30
suy ra 5x=30
x= 6
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`(x+2)-2=0`
`=>x+2=0+2`
`=>x+2=2`
`=>x=2-2`
`=>x=0`
__
`(x+3)+1=7`
`=>x+3=7-1`
`=>x+3=6`
`=>x=6-3`
`=>x=3`
__
`(x+3)+4=12`
`=>x+3=12-4`
`=>x+3=8`
`=>x=8-3`
`=>x=5`
__
`(5x+4)-1=13`
`=>5x+4=13+1`
`=>5x+4=14`
`=>5x=14-4`
`=>5x=10`
`=>x=10:5`
`=>x=2`
__
`(4x-8)+3=12`
`=>4x-8=12-3`
`=>4x-8=9`
`=>4x=9+8`
`=>4x=17`
`=> x=17/4`
__
`3+(x-5)=14`
`=>x-5=14-3`
`=>x-5=11`
`=>x=11+5`
`=>x=16`
\(\frac{5x}{14}+\frac{5}{7}=\frac{14}{3}\)
\(\frac{5x}{14}=\frac{14}{3}-\frac{5}{7}\)
\(\frac{5x}{14}=\frac{83}{21}\)
\(5x=\frac{83.14}{21}\)
\(5x=\frac{166}{3}\)
\(x=\frac{166}{3}:5\)
\(x=\frac{166}{15}\)
\(\frac{5x}{14}+\frac{5}{7}=\frac{14}{3}\Leftrightarrow\)\(\frac{5x}{14}=\frac{14}{3}-\frac{5}{7}=\frac{83}{21}\Leftrightarrow x=\frac{83}{21}\cdot\frac{14}{5}=\frac{166}{15}=11\frac{1}{15}\)