5x + x + 39 - 311 : 39
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a) \(5x+x=39-3^{11}:3^9\)
\(\Leftrightarrow6x=39-3^2\)
\(\Leftrightarrow6x=30\)
\(\Leftrightarrow x=5\)
b) \(2^x:2^5=16\)
\(\Leftrightarrow2^x:2^5=2^4\)
\(\Leftrightarrow2^x=2^4.2^5\)
\(\Leftrightarrow2^x=2^9\)
\(\Leftrightarrow x=9\)
c) \(7x-x=5^{21}:5^{19}+3.2^2-7^0\)
\(\Leftrightarrow6x=5^2+3.4-1\)
\(\Leftrightarrow6x=36\)
\(\Leftrightarrow x=6\)
d) \(7x-2x=6^{17}:6^{15}+44:11\)
\(\Leftrightarrow5x=6^2+4\)
\(\Leftrightarrow5x=40\)
\(\Leftrightarrow x=8\)
a)⇔6x=39-32
⇔6x=30
⇔ x=5
b)2x:25=16
⇔2x=24.25
⇔ 2x=29
⇔ x=9
c)⇔6x=52+3.22-1
⇔ 6x= 36
⇔ x=6
d)⇔5x=62+4
⇔ 5x=40
⇔ x=8
![](https://rs.olm.vn/images/avt/0.png?1311)
a: \(\Leftrightarrow6x=30\)
hay x=5
b: \(\Leftrightarrow6x=25+12-1=36\)
hay x=6
![](https://rs.olm.vn/images/avt/0.png?1311)
a: \(\Leftrightarrow8x=108+12=120\)
hay x=15
b: \(\Leftrightarrow6x=60\)
hay x=10
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b: Ta có: 7x-8=713
nên 7x=721
hay x=103
c: Ta có: x-36:18=12
nên x-2=12
hay x=14
d: Ta có: (x-36):18=12
nên x-36=216
hay x=252
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\(4^3\cdot4^{x-1}=64\)
\(\Leftrightarrow4^{x-1}=1\)
\(\Leftrightarrow x-1=0\)
hay x=1
![](https://rs.olm.vn/images/avt/0.png?1311)
a: 3x=81
nên x=27
b: \(5\cdot4^x=80\)
\(\Leftrightarrow4^x=16\)
hay x=2
c: \(2^x=4^5:4^3\)
\(\Leftrightarrow2^x=2^4\)
hay x=4
![](https://rs.olm.vn/images/avt/0.png?1311)
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\(180:\left\{\left(-30\right)+\left[4^2.5-\left(14+3^{11}:3^9\right)\right]\right\}\)
\(=180:\left\{\left(-30\right)+\left[16.5-\left(14+3^{11}.\dfrac{1}{3^9}\right)\right]\right\}\)
\(=180:\left\{\left(-30\right)+\left[80-\left(14+3^2\right)\right]\right\}\)
\(=180:\left\{\left(-30\right)+\left[80-\left(14+9\right)\right]\right\}\)
\(=180:\left[\left(-30\right)+80-23\right]\)
\(=180:27\\ =\dfrac{20}{3}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
Ta có: \(\widehat{xOy}+\widehat{yOx'}=180^0\)(kề bù)
\(\Rightarrow5x+4x=180^0\)
\(\Rightarrow9x=180^0\Rightarrow x=20^0\)
\(\Rightarrow\left\{{}\begin{matrix}\widehat{xOy}=5x=5.20^0=100^0\\\widehat{yOx'}=4x=4.20^0=80^0\end{matrix}\right.\)
Vì xOx'kề bù nên:xOy+yOx'=180 độ
=>5x+4x=180 độ
x.9=180 độ =>x=20 độ
=>xOy=20x5=100 độ
=>yOx'=20x4=80 độ
HT
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a)3\(^{11}\):3\(^9\)−147:7\(^2\)
=3\(^{11}\)\(^{-9}\)−147:49
=3\(^2\)−147:49
=9−3
=6
b)295−(31−22×5)w)295-(31-22×5)
=295−(31−2\(^2\).5)\(^2\)
=295−11\(^2\)
=295−121
=174
đề thế này phải ko?
5x + x + 39 = 311 : 39
5x + x + 39 = 311-9
5x + 1x + 39 = 32
(5+1)x + 39 = 9
6x = 9 + 39
6x = 48
x = 48 : 6
x = 8
đúng ko?