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\(\left|x+2\right|=0\)
\(\Rightarrow x+2=0\)
\(\Rightarrow x=0-2\)
\(\Rightarrow x=-2\)
\(\left|x-5\right|=\left|-7\right|\)
\(\Rightarrow\left|x-5\right|=7\)
\(\Rightarrow\hept{\begin{cases}x-5=-7\\x-5=7\end{cases}}\Leftrightarrow\hept{\begin{cases}x=-7+5\\x=7+5\end{cases}}\Leftrightarrow\hept{\begin{cases}x=-2\\x=12\end{cases}}\)
\(\Rightarrow x\in\left\{-2;12\right\}\)
a) x - 7 = - 5
x = - 5 + 7
x = 2
b) 128 - 3 . ( x + 4 ) = 23
3 . ( x + 4 ) = 128 - 23
3 . ( x + 4 ) = 105
x + 4 = 105 : 3
x + 4 = 35
x = 35 - 4
x = 31
c) [ ( 6x - 39 ) : 7 ] . 4 = 12
( 6x - 39 ) : 7 = 12 : 4
( 6x - 39 ) : 7 = 3
6x - 39 = 3 . 7
6x - 39 = 21
6x = 60
x = 10
d) ( x : 3 - 4 ) . 5 = 15
x : 3 - 4 = 3
x : 3 = 7
x = 21
a) x - 7= -5
x= -5 +7
x= 2
b) 128 -3 .(x+4)=23
3.(x+4)=128-23
3.(x+4)=105
x+4=105:3
x+4=35
x=35-4
x=31
c)[(6x-39):7].4=12
[(6x-39):7]=12:4
(6x-39):7=3
6x-39=7.3
6x-39=21
6x=21+39
6x=60
x=60:6
x=10
d) ( x :3 -4).5=15
x:3-4=15:5
x:3-4=3
x:3=4+3
x:3=7
x=7.3
x=21
e)(3x -2^4 ).7^3=2. 7^4
(3x-16).343=2.2401
(3x-16).343=4802
3x-16=4802:343
3x-16=14
3x=14+16
3x=30
x=30:3
x=10
g)x-[ 42+(-28)]=-8
x-14=-8
x=-8+14
x=6
i) 4-(7-x)=x -(13-4)
4-7+x=x-13+4
-3 + x= x-9
-3+x=-9+x
=> K có giá trị nào thỏa mãn -3+x=-9+x
=>x thuộc rỗng
1/ 3(x - 2) = 9 => x - 2 = 3 => x = 5
2/ 3(x - 36) = 216 => x - 36 = 72 => x = 108
3/ (x - 3)3 = 33 => x - 3 = 3 => x = 6
4/ 2x = 32 => 2x = 25 => x = 5
5/ 3x - 16 = 2.74 : 73 = 14 => 3x = 30 => x = 10
6/ (6x - 39) : 3 = 201 => 6x - 39 = 603 => 6x = 642 => x = 107
7/ (3x - 15)2 = 81 => (3x - 15)2 = 92 => 3x - 15 = 9 => 3x = 24 => x = 8
8/ 3(x + 4) = 105 => x + 4 = 35 => x = 31
9/ 12x - 43 = 4.84 : 83 = 32 => 12x = 32 : 64 => 12x = 1/2 => x = 1/24
10/ 41 - (2x - 5) = 680 => 2x - 5 = -639 => 2x = -634 => x = - 317
a; -2\(x\) - 3.(\(x-17\)) = 34 - 2.( - \(x\) + 25)
- 2\(x\) - 3\(x\) + 51 = 34 + 2\(x\) - 50
2\(x\) + 2\(x\) + 3\(x\) = - 34 + 50 + 51
7\(x\) = 67
\(x\) = 67 : 7
\(x\) = \(\dfrac{67}{7}\)
Vậy \(x\) = \(\dfrac{67}{7}\)
b; 17\(x\) + 3.(- 16\(x\) - 37) = 2\(x\) + 43 - 4\(x\)
17\(x\) - 48\(x\) - 111 = 2\(x\) - 4\(x\) + 43
- 31\(x\) - 2\(x\) + 4\(x\) = 111 + 43
- \(x\) x (31 + 2 - 4) = 154
- \(x\) x (33 - 4) = 154
- \(x\) x 29 = 154
- \(x\) = 154 : (-29)
\(x\) = - \(\dfrac{154}{29}\)
Vậy \(x=-\dfrac{154}{29}\)
c)
\(4\left(3x-4\right)-2=18\)
<=> \(12x-16-2=18\)
<=> \(12x=36\)
<=> \(x=3\)
Vậy x=3
d)
\(\left(3x-10\right):10=50\)
<=> \(3x-10=500\)
<=> \(3x=510\)
<=> x= \(170\)
Vậy x= 170
f)
\(x-\left[42+\left(-25\right)\right]=-8\)
<=> \(x-17=-8\)
<=> x= \(9\)
Vậy x=9
h)
\(x+5=20-\left(12-7\right)\)
<=> \(x+5=15\)
<=> \(x=10\)
Vậy x= 10
k)
\(\left|x-5\right|=7-\left(-3\right)\)
<=> \(\left|x-5\right|=10\)
* Với \(x>=5\) ; ta được:
\(x-5=10\)
<=> x= 15 (thoả mãn điều kiện )
*Với \(x< 5\) ; ta được:
\(-\left(x-5\right)=10\)
<=> \(-x+5=10\)
<=> \(-x=5\)
<=> \(x=-5\) (thoả mãn điều kiện)
Vậy x=15 ; x= -5
i)
\(\left|x-5\right|=\left|7\right|\)
<=> \(\left|x-5\right|=7\)
*Với \(x>=5\) ; ta được:
\(x-5=7\)
<=> \(x=12\) (thoả mãn)
*Với \(x< 5\) ; ta được:
\(-\left(x-5\right)=7\)
<=> \(-x=2\)
<=> \(x=-2\) (thoả mãn)
Vậy x= 12; x= -2
m)
\(2^{x+1}.2^{2009}=2^{2010}\)
<=> \(2^{x+1+2009}=2^{2010}\)
<=> \(2^{x+2010}=2^{2010}\)
=> \(x+2010=2010\)
=> \(x=0\)
Vậy x=0
n)
\(10-2x=25-3x\)
<=>\(x=15\)
Vậy x=15
a) (x : 3 - 4) . 5 = 15
x : 3 - 4 = 15 : 5
x : 3 - 4 = 3
x : 3 = 3 + 4
x : 3 = 7
x = 7 . 3
x = 21.
b) 128 - 3 . (x + 4) = 23
3 . (x + 4) = 128 - 23
3 . (x + 4) = 105
x + 4 = 105 : 3
x + 4 = 35
x = 35 - 4
x = 31.
c) (3x - 24) . 73 = 2 . 74
3x - 24 = 2 . 74 : 73
3x - 24 = 2 . 7
3x - 16 = 14
3x = 14 + 16
3x = 30
x = 30 : 3
x = 10.
d) 5x + x = 39 - 311 : 39
5x + x = 39 - 32
5x + x = 39 - 9
6x = 30
x = 30 : 6
x = 5.
a) \(\left(\dfrac{x}{3}-4\right).5=15\)
\(\Leftrightarrow\dfrac{x}{3}-4=\dfrac{15}{5}\)
\(\Leftrightarrow\dfrac{x}{3}-4=3\)
\(\Leftrightarrow\dfrac{x}{3}=3+4\)
\(\Leftrightarrow\dfrac{x}{3}=7\)
\(\Leftrightarrow x=7.3\)
\(\Leftrightarrow x=21\)
Vậy \(x=21\)
b) \(128-3\left(x+4\right)=23\)
\(\Leftrightarrow3\left(x+4\right)=128-23\)
\(\Leftrightarrow3\left(x+4\right)=105\)
\(\Leftrightarrow x+4=\dfrac{105}{3}\)
\(\Leftrightarrow x+4=35\)
\(\Leftrightarrow x=35-4\)
\(\Leftrightarrow x=31\)
Vậy \(x=31\)
c) \(\left(3x-2^4\right).7^3=2.7^4\)
\(\Leftrightarrow3x-2^4=\dfrac{2.7^4}{7^3}\)
\(\Leftrightarrow3x-2^4=2.7\)
\(\Leftrightarrow3x-2^4=14\)
\(\Leftrightarrow3x-16=14\)
\(\Leftrightarrow3x=14+16\)
\(\Leftrightarrow3x=30\)
\(\Leftrightarrow x=\dfrac{30}{3}\)
\(\Leftrightarrow x=10\)
Vậy \(x=10\)
d) \(5x+x=39-3^{11}:3^9\)
\(\Leftrightarrow6x=39-3^{11-9}\)
\(\Leftrightarrow6x=39-3^2\)
\(\Leftrightarrow6x=39-9\)
\(\Leftrightarrow6x=30\)
\(\Leftrightarrow x=\dfrac{30}{6}\)
\(\Leftrightarrow x=5\)
Vậy \(x=5\)
Bài 1:
1; ( - 35) : (-7) = 5
2; (- 42) : 21 = - 2
3; 45 : (-9) = -5
4; 18 : 9 = 2
5; (- 30) : (- 15) = 2
6; 0 : 18 = 0
7; 0 : (-13) = 0
8; 44 : (-4) = - 11
9; - 55 : 11 = - 5
10; 46 : 23 = 2
x-7=-5
x=-5+7
x=2
vậy x=2
128-3.(x+4)=23
3.(x+4)=128-23
3.(x+4)=105
x+4=105:3
x+4=35
x=35-4
x=31
vậy x=31
|x+2|=0
x+2=0
x=0-2
x=-2
vậy x=-2
|x-5|=|-7|
x-5=7
x=7+5
x=12
vậy x=12