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a, 11 - ( 15 + 11 ) = x - ( 25 - 9 )
11-15-11=x-25+9
-15=x-16
x=1
b, 2 - x = 17 - ( - 5 )
2-x=22
x=-20
c, x - 12 = ( - 9 ) - 15
x-12=-24
x=-12
d, 9 - 25 = ( 7 - x ) - ( 25 + 7 )
(7-x)-32=-16
7-x=16
x=-9
#H
a) 15 – ( 4 – x) = 6
=> 4 – x= 15 - 6
=> 4 – x= 9
=> x= 4 - 9
=> x= -5
Easy!
a) \(15-\left(4-x\right)=6\)
\(\Leftrightarrow4-x=15-6\)
\(\Leftrightarrow4-x=9\)
\(\Leftrightarrow x=4-9\)
\(\Leftrightarrow x=-5\)
Vậy \(x=-5\)
b) \(-30+\left(25-x\right)=-1\)
\(\Leftrightarrow\left(25-x\right)=-1-\left(-30\right)\)
\(\Leftrightarrow25-x=29\)
\(\Leftrightarrow x=25-29\)
\(\Leftrightarrow x=-4\)
c) \(x-\left(12-25\right)=-8\)
\(\Leftrightarrow x-\left(-13\right)=-8\)
\(\Leftrightarrow x=-8+-13\)
\(\Leftrightarrow x=-21\)
Vậy \(x=-21\)
d) \(\left(x-29\right)-\left(17-38\right)=-9\)
\(\Leftrightarrow\left(x-29\right)-\left(-21\right)=-9\)
\(\Leftrightarrow x-29=-9+\left(-21\right)\)
\(\Leftrightarrow x-29=-30\)
\(\Leftrightarrow x=-30+29\)
\(\Leftrightarrow x=-1\)
Vậy \(x=-1\)
a) x - (17 - 8) = 5 + (10 - 3x)
x - 17 + 8 = 5 + 10 - 3x
x + 3x = 5 + 10 + 17 - 8
4x = 24
x = 24 : 4
x = 6
b) 25 - (30 + x) = x - (27 - 8)
25 - 30 - x = x - 27 + 8
-x - x = -27 + 8 - 25 + 30
-2x = -14
x = (-14) : (-2)
x = 7
c) (x - 12) - 15 = (20 - 7) - (18 + x)
x - 12 - 15 = 20 - 7 -18 - x
x + x = 20 - 7 - 18 + 12 + 15
2x = 22
x = 22 : 2
x = 11
d) 9 - 25 = (7 - x) - (25 + 7)
9 - 25 = 7 - x - 25 - 7
x = 7 - 25 - 7 - 9 +25
x = -9
a, 27+(-17+x)=297-(12+297)
27-17+x=297-12-297
10+x=-12
x=-22
b,25-(-2+x+25)= -(-10-397)+(-397-5)
25+2-x-25=10+397-397-5
2-x=5
x=-3
c, (32-x)+(-7+/x/)-(/-x/+25)=-45
* TH1: x>=0, ta có /x/=x , /-x/=-x
32-x+(-7+x)-(-x+25)=-45
32-x-7+x+x-25=-45
x=-45
*TH2:x<0, ta có /x/=-x, /-x/=x
32-x-7-x-x-25=-45
-3x=-45
x=15
\(x\left(x-2\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x=0\\x-2=0\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=0\\x=2\end{cases}}\)
a) <=> 15-5x-20=-12-3
<=> -5x=-12-3-15+20=-10
=>x=-10:(-5)=2
b)<=>7-x-25-7=-25
<=> -x=-25-7+25+7=0 =>x=0
c) /x+2/=0 => x+2=0 =>x=-2
d) sai đề
e)<=> /x-5/ = 7
<=> \(\orbr{\begin{cases}x-5=7\\x-5=-7\end{cases}}\)
<=> \(\orbr{\begin{cases}x=12\\x=-2\end{cases}}\)
g) <=> -x-20-8+2x=-15
<=> x=-15+20+8=13
a. x- (17 - x) = x-7
x-17+x = x+7
2x-17=x+7
2x-x= 7+17
x= 24
b. 9-25=(7-x)-(25+7)
-16=7-x-25-7
-16=-x-25
x= -25 + 16
x = -9
c. (-12)^2 .x = 56 + 10.13.x
144x = 56 + 130x
144x - 130x = 56
14x=56
x= 56 : 14
x= 4
d. 4/24 : (3x-2) = -3
4/24 = -3.(3x-2)
4/24 = -9x + 6
9x = 6 - 4/24
9x = 35/6
x= 35/6 :9
x= 35/54
e. 5/-45 chia hay nhân với (-3-2x) nhỉ
a, => x = 5 - 13 = -8
b, => x = -9 + 1 = -8
c, => |x| = 25 - 10 = 15
=> x = 15 hoặc x = -15
d, => |x-2| = 12 - 7 = 5
=> x-2 =5 hoặc x-2 = -5
=> x=7 hoặc x=-3
`Answer:`
a. \(x+12=3\Leftrightarrow x=3-12\Leftrightarrow x=-9\)
b. \(2x-15=21\Leftrightarrow2x=21+15\Leftrightarrow2x=36\Leftrightarrow x=36:2\Leftrightarrow x=18\)
c. \(13-3x=4\Leftrightarrow-3x=4-13\Leftrightarrow-3x=-9\Leftrightarrow x=-9:-3\Leftrightarrow x=3\)
d. \(2\left(x-2\right)+4=12\Leftrightarrow2x-4+4=12\Leftrightarrow2x=12\Leftrightarrow x=12:2\Leftrightarrow x=6\)
e. \(15-3\left(x-2\right)=21\Leftrightarrow15-3x+6=21\Leftrightarrow-3x=21-15-6\Leftrightarrow-3x=0\Leftrightarrow x=0\)
g. \(25+4\left(3-x\right)=1\Leftrightarrow25+12-4x=1\Leftrightarrow37-4x=1\Leftrightarrow-4x=-36\Leftrightarrow x=9\)
h. \(3x+12=2x-4\Leftrightarrow3x-2x=-4-12\Leftrightarrow x=-16\)
i. \(14-3x=\left(-x\right)+4\Leftrightarrow-3x+x=4-14\Leftrightarrow-2x=10\Leftrightarrow x=5\)
k. \(2\left(x-2\right)+7=x-25\Leftrightarrow2x-4+7=x-25\Leftrightarrow2x-x=-25-3\Leftrightarrow x=-28\)
Đáp án cần chọn là: B
121212 252525 = 121212 : 10101 252525 : 10101 = 12 25 = x 25 nên x=12