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\(4x\cdot\left(x:2\right)-3\left(1-2x\right)=7-2\left(x+1\right)\)
\(\Leftrightarrow4x\cdot\dfrac{x}{2}-3+6x=7-2x-2\)
\(\Leftrightarrow2x\cdot x-3+6x=5-2x\)
\(\Leftrightarrow2x^2-3+6x=5-2x\)
\(\Leftrightarrow2x^2-3+6x-5+2x=0\)
\(\Leftrightarrow2x^2-8+8x=0\)
\(\Leftrightarrow2\left(x^2-4+4x\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-2+2\sqrt{2}\\x=-2-2\sqrt{2}\end{matrix}\right.\)
Vậy \(x_1=-2-2\sqrt{2};x_2=-2+2\sqrt{2}\)
\(4x\left(x:2\right)-3x\left(1-2x\right)=7-2\left(x+1\right)\)
\(\Leftrightarrow4x.\dfrac{x}{2}-3+6x-7+2x+2=0\Leftrightarrow2x^2+8x-8=0\Leftrightarrow2\left(x^2+4x-4\right)=0\)
\(\Leftrightarrow\left(x^2+4x+4\right)-8=0\)
\(\Leftrightarrow\left(x+2\right)^2=8\Rightarrow\left[{}\begin{matrix}x-2=\sqrt{8}\\x-2=-\sqrt{8}\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\sqrt{2}+2\\x=-\sqrt{8}+2\end{matrix}\right.\)
\(=>9x+2=60:3\)
\(=>9x+2=20\)
\(=>9x=20-2\)
\(=>9x=18\)
\(=>x=18:2=2\)
Vậy số cần tìm là 2
CHÚC BẠN HỌC TỐT............
( 9x + 2 ) . 3 = 60
( 9x + 2 ) = 60 : 3
9x + 2 = 20
9x = 20 - 2
9x =18
x = 18 : 9
x = 2
Tuy có vẻ hơi muộn nhưng thôi 
Nếu A là số tự nhiên ⇒ \(\dfrac{1}{10}\left(7^{2004}-3^{92^{94}}\right)\in N\)
\(\Rightarrow7^{2004}-3^{92^{94}}⋮10\)
Thật vậy, ta có :
72004 với lũy thừa là 2004 ⋮ 4
⇒ 72004 = ( .......... 9 )
392^94 với lũy thừa là 9294 mà 92 ⋮ 4 ⇒ 9294 ⋮ 4
⇒ 392^94 = ( .......... 9 )
⇒ 72004 - 392^94 = ( .......... 9 ) - ( ............ 9) = ( ........... 0 ) ⋮ 10
⇒ \(\dfrac{1}{10}\left(7^{2004}-3^{92^{94}}\right)\in N\)
A=1/10.(72004-392^94) là số tự nhiên.
Ta có: \(\left|x-y\right|+\left|x-1\right|\ge0\)
\(\Rightarrow A=\left|x-y\right|+\left|x-1\right|+2017\ge2017\)
Dấu " = " khi \(\left\{{}\begin{matrix}\left|x-y\right|=0\\\left|x-1\right|=0\end{matrix}\right.\Rightarrow x=y=1\)
Vậy \(MIN_A=2017\) khi x = y = 1
a) ( x - 25 ) - 120 = 3
x - 25 = 3 + 120
x - 25 = 123
x = 123 + 25
x = 148
b) 156 - ( x + 61 ) = 82
x + 61 = 156 - 82
x + 61 = 74
x = 74 - 61
x = 13
Vậy x = 13
1/ a, \(50-\left[30-\left(6-2\right)^2\right]\)
\(=50-\left[30-3^2\right]\)
\(=50-30+9\)
\(=20+9=29\)
2/ a, \(124+\left(118-x\right)=217\)
\(\Leftrightarrow118-x=3\)
\(\Leftrightarrow x=115\)
Vậy ...
b/ \(814-\left(x-305\right)=712\)
\(\Leftrightarrow x-305=102\)
\(\Leftrightarrow x=407\)
Vậy ...
c/ \(x-32:16=48\)
\(\Leftrightarrow x-2=48\)
\(\Leftrightarrow x=50\)
Vậy ...
d/ \(\left(x-32\right):16=48\)
\(\Leftrightarrow x-32=768\)
\(\Leftrightarrow x=800\)
Vậy .
a) |3-x|=7
=> 3-x=7 hay 3-x=-7
Với 3-x=7
x=3-7
x=-4
Với 3-x=-7
x=3-(-7)
x=10
Vậy x \(\in\){-4;10}
b) |x| < 4
=>x<4
Vậy x\(\in\){3;2;1;0;-1;-2;-3}
a, |3 - x| = 7
\(\Rightarrow\left\{\begin{matrix}3-x=7\\3-x=-7\end{matrix}\right.\Rightarrow\left\{\begin{matrix}x=-4\\x=10\end{matrix}\right.\)
b, |x| < 4
=> x = {-3;-2;-1;0;1;2;3}
a ) | 2x - 1 | = | -7 |
| 2x - 1 | = 7
+ ) 2x - 1 = 7
2x = 8
x = 4
+ ) 2x - 1 = -7
2x = -6
x = -3
Vậy .........
b ) | x + 5 | = 0
x + 5 = 0
x = -5
Vậy ............
c ) 8x - 75 = 5x + 21
8x - 5x = 21 + 75
3x = 96
x = 32
Vậy .......
d ) 9x + 25 = -2x + 58
9x + 2x = 58 - 25
11x = 33
x = 3
Vậy ........
a, \(\left|2x-1\right|=\left|-7\right|\Rightarrow\left|2x-1\right|=7\)
\(\Rightarrow2x-1\in\left\{-7;7\right\}\)
+) \(2x-1=7\Rightarrow2x=7+1\)
\(\Rightarrow2x=8\Rightarrow x=8\div2=4\)
+) \(2x-1=-7\Rightarrow2x=-7+1\)
\(\Rightarrow2x=-6\Rightarrow x=-6\div2=-3\)
Vậy \(x\in\left\{-3;4\right\}\)
b, \(\left|x+5\right|=0\Rightarrow x+5=0\)
\(\Rightarrow x=0-5\Rightarrow x=-5\)
Vậy x = -5
c, \(8x-75=5x+21\Rightarrow8x-5x=21+75\)
\(\Rightarrow\left(8-5\right)x=96\Rightarrow3x=96\)
\(\Rightarrow x=96\div3\Rightarrow x=32\)
Vậy x = 32
d, \(9x+25=-\left(2x-58\right)\Rightarrow9x+25=-2x+58\)
\(\Rightarrow9x+2x=58-25\Rightarrow\left(9+2\right)x=33\)
\(\Rightarrow11x=33\Rightarrow x=33\div11\Rightarrow x=3\)
Vậy x = 3