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2 tháng 9 2021
a)96-3(x+8)=42
3(x+8)=96-42
3(x+8)=54
x+8=54:3
x+8=18
x=18-8
x=10
b)36:(x-5)=2^
36:(x-5)=4
(x-5)=36:4
x-5=9
x=9+5
x=14
2 tháng 9 2021
c)15.5(x-35)-525=0
75(x-35)=0+525
x-35=525:75
x-35=7
x=7+35
x=42
d)[3.(70-x)+5]:2=46
3.(70-x)+5=46x2
3.(70-x)+5=92
3.(70-x)=92-5
3.(70-x)=87
70-x=87:3
70-x=29
x=70-29
x=41
HT
22 tháng 10 2019
1. \(6x^3-8=40\\ 6x^3=48\\ x^3=8\\ \Rightarrow x=2\)Vậy x = 2
2. \(4x^5+15=47\\ 4x^5=32\\ x^5=8\\ \Rightarrow x\in\varnothing\left(\text{vì }x\in N\right)\)Vậy x ∈ ∅
3. \(2x^3-4=12\\ 2x^3=16\\ x^3=8\\ \Rightarrow x=2\)Vậy x = 2
4. \(5x^3-5=0\\ 5x^3=5\\ x^3=1\\ \Rightarrow x=1\)Vậy x = 1
5. \(\left(x-5\right)^{2016}=\left(x-5\right)^{2018}\\ \Rightarrow\left[{}\begin{matrix}x-5=0\\x-5=1\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=5\\x=6\end{matrix}\right.\)Vậy \(x\in\left\{5;6\right\}\)
6. \(\left(3x-2\right)^{20}=\left(3x-1\right)^{20}\\ \Rightarrow3x-2=3x-1\\ 3x-3x=2-1\\ 0=1\left(\text{vô lí}\right)\)Vậy x ∈ ∅
7. \(\left(3x-1\right)^{10}=\left(3x-1\right)^{20}\\ \left(3x-1\right)^{10}=\left[\left(3x-1\right)^2\right]^{10}\\ \Rightarrow\left(3x-1\right)^2=3x-1\\ \left(3x-1\right)^2-\left(3x-1\right)=0\\ \left(3x-1\right)\left[\left(3x-1\right)-1\right]=0\\ \left(3x-1\right)\left(3x-2\right)=0\\ \Rightarrow\left[{}\begin{matrix}3x-1=0\\3x-2=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}3x=1\\3x=2\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\frac{1}{3}\left(\text{loại vì }x\in N\right)\\x=\frac{2}{3}\left(\text{loại vì }x\in N\right)\end{matrix}\right.\)Vậy x ∈ ∅
8. \(\left(2x-1\right)^{50}=2x-1\\ \left(2x-1\right)^{50}-\left(2x-1\right)=0\\ \left(2x-1\right)\left[\left(2x-1\right)^{49}-1\right]=0\\ \Rightarrow\left[{}\begin{matrix}2x-1=0\\\left(2x-1\right)^{49}=1\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}2x=1\\2x-1=1\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=\frac{1}{2}\left(\text{loại vì }x\in N\right)\\x=1\left(t/m\right)\end{matrix}\right.\)Vậy x = 1
9. \(\left(\frac{x}{3}-5\right)^{2000}=\left(\frac{x}{3}-5\right)^{2008}\\ \left(\frac{x}{3}-5\right)^{2008}-\left(\frac{x}{3}-5\right)^{2000}=0\\ \left(\frac{x}{3}-5\right)^{2000}\left[\left(\frac{x}{3}-5\right)^8-1\right]=0\\ \Rightarrow\left[{}\begin{matrix}\left(\frac{x}{3}-5\right)^{2000}=0\\\left(\frac{x}{3}-5\right)^8=1\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}\frac{x}{3}-5=0\\\frac{x}{3}-5=1\\\frac{x}{3}-5=-1\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}\frac{x}{3}=5\\\frac{x}{3}=6\\\frac{x}{3}=4\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=5\cdot3=15\\x=6\cdot3=18\\x=4\cdot3=12\end{matrix}\right.\)Vậy \(x\in\left\{15;18;12\right\}\)
22 tháng 10 2019
\(1.6x^3-8=40\\ \Leftrightarrow6x^3=48\\ \Leftrightarrow x^3=8\Leftrightarrow x^3=2^3=\left(-2\right)^3\Leftrightarrow\left[{}\begin{matrix}x=2\\x=-2\end{matrix}\right.\)
Vậy \(x\in\left\{2;-2\right\}\)
\(2.4x^3+15=47\) (T nghĩ đề là mũ 3)
\(\Leftrightarrow4x^3=32\Leftrightarrow x^3=8=2^3=\left(-2\right)^3\Leftrightarrow\left[{}\begin{matrix}x=2\\x=-2\end{matrix}\right.\)
Vậy \(x\in\left\{2;-2\right\}\)
Câu 3, 4 tương tự nhé.
TN
22 tháng 6 2016
a) 541 + ( 281 - x ) =735
=>281-x=735-541
=>281-x=194
=>x=87
b)5.(x+35) = 515
=>x+35=515:5
=>x+35=103
=>x=68
c)96 - 3.( 9x+1) =42
=>3(9x+1)=96-42
=>3(9x+1)=54
=>9x+1=18
=>9x=17
=>x=17/9
d)12x-33=32*33
=>12x-33=9*27
=>12x-33=243
=>12x=276
=>x=23
HR
1
17 tháng 9 2018
541 + ( 218 -x ) = 735 5 ( x + 35 ) = 515
218-x = 735 - 541 5 . ( x+ 35 ) =515
218-x = 194 x+ 35 = 515 : 5
x =218-194 x + 35 = 103
x = 24 x = 103 - 35
x = 68
96- 3 ( x+ 1 ) = 42 12x - 33 = 3^2 3^3
93 . ( x+ 1 ) = 42 12x -33 =9 . 27
x + 1 =93 : 42 12x -33 = 243
x + 1 = 31/14 12x = 243 + 33
x = 31/14 - 1 12x = 276
x = 31/14 - 1/1 x = 276 : 12
x = 31/14 - 14/14 x = 23
x = 17/14
a) =45
b) =100
c) =10
d) =42
\(\left(2x+1\right):7=2^2+3^2 \)
\(\Leftrightarrow\left(2x+1\right):7=13\)
\(\Leftrightarrow2x+1=13.7\)
\(\Leftrightarrow2x+1=91\)
\(\Leftrightarrow2x=90\)
\(\Leftrightarrow x=45\)
\(400-x.3=100\)
\(\Leftrightarrow-x.3=400-100\)
\(\Leftrightarrow-x.3=300\)
\(\Leftrightarrow-x=300:3\)
\(\Leftrightarrow x=100\)
\(96-3\left(x+8\right)=42\)
\(\Leftrightarrow3\left(x+8\right)=96-42\)
\(\Leftrightarrow3\left(x+8\right)=54\)
\(\Leftrightarrow x+8=54:3\)
\(\Leftrightarrow x+8=18\)
\(\Leftrightarrow x=10\)
\(15.5\left(x-35\right)-525=0\)
\(\Leftrightarrow75\left(x-35\right)-525=0\)
\(\Leftrightarrow75\left(x-35\right)=525\)
\(\Leftrightarrow75x-2625=525\)
\(\Leftrightarrow75x=525+5625\)
\(\Leftrightarrow75x=3150\)
\(\Leftrightarrow x=42\)
- Chúc bạn làm bài tốt !