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a, -121 - [-35 - x] = 50
<=> -35 - x = -121 - 50
<=> -35 - x = -171
<=> x = -171 + [-35] = -206
Vậy x = -206
b, 17 + x - [352 - 400] = -32
<=> 17 + x - [-48] = -32
<=> 17 + x + 48 = -32
<=> 17 + x = -32 - 48
<=> 17 + x = -80
<=> x = -80 - 17
<=> x = -97
Vậy x = -97
c, 2130 - [x + 130] + 72 = -64
<=> 2130 - [x + 130] = -64 - 72
<=> 2130 - [x + 130] = -136
<=> x + 130 = 2130 - [-136]
<=> x + 130 = 2130 + 136
<=> x + 130 = 2266
<=> x = 2266 - 130 = 2136
d, |x| - 5 = -1
<=> |x| = -1 + 5
<=> |x| = 4
<=> x = 4 hoặc x = -4
e, |x+ 2| - 12 = -1
<=> |x + 2| = -1 + 12
<=> |x + 2| = 11
<=> x + 2 = 11 hoặc x + 2 = -11
<=> x = 11 - 2 hoặc x = -11 - 2
<=> x = 9 hoặc x = -13
f,g Tương tự
a) -121 - (-35 - x) = 50
-121 + 35 + x = 50
x - 86 = 50
x = 50 + 86
x = 136
b) 17 + x - (352 - 400) = -32
17 + x - 352 + 400 = -32
x + 65 = -32
x = -32 - 65
x = -97
c) 2130 - (x + 130) + 72 = -64
2130 - x - 130 + 72 = -64
2072 - x = -64
-x = -64 - 2072
-x = -2136
x = 2136
d) |x| - 5 = -1
|x| = -1 + 5
|x| = 4
x = 4; -4
e) |x + 2| - 12 = -1
|x + 2| = -1 + 12
|x + 2| = 11
x + 2 = 11; -11
x + 2 = 11 hoặc x + 2 = -11
x = 11 - 2 x = -11 - 2
x = 9 x = -13
f) 135 - |9 - x| = 35
-|9 - x| = 35 - 135
-|9 - x| = -100
|9 - x| = 100
9 - x = 100; -100
9 - x = 100 hoặc 9 - x = -100
x = 100 + 9 x = -100 + 9
x = 109 x = -91
c) 135 - | 9 - x | = 3
| 9 - x | = 135 - 3
| 9 - x | = 132
=> 9 - x = 132
x = 9 - 132
x = 123
hoặc 9 - x = - 132
x = 9 - ( - 132 )
x = 9 + 132
x = 141
Vậy ..................
c) 135 - | 9 - x | = 35
\(2\left(x-1\right)+3\left(x-2\right)=x-4\)
\(2x-2+3x-6=x-4\)
\(5x-8=x-4\)
\(5x-8-x+4=0\)
\(4x-4=0\)
\(4x=4\)
\(x=1\)
\(3\left(4-x\right)-2\left(x-1\right)=x+20\)
\(12-x-2x+2=x+20\)
\(14-3x=x+20\)
\(14-3x-x-20=0\)
\(-6-4x=0\)
\(4x=-6\)
\(x=-\frac{3}{2}\)
\(\left|2x+3\right|=5\)
\(\Rightarrow\orbr{\begin{cases}2x=2\\2x=-8\end{cases}\Rightarrow\orbr{\begin{cases}x=1\\x=-4\end{cases}}}\)
a) \(\left|x-2\right|-12=-1\)
\(\Leftrightarrow\left|x-2\right|=11\)
TH1 : \(x-2=11\)
\(\Leftrightarrow x=13\)
TH2 : \(x-2=-11\)
\(\Leftrightarrow x=-9\)
Vậy \(x\in\left\{13;-9\right\}\)
b) \(135-\left|9-x\right|=35\)
\(\Leftrightarrow\left|9-x\right|=100\)
TH1 : \(9-x=100\)
\(\Leftrightarrow x=-91\)
TH2 :\(9-x=-100\)
\(\Leftrightarrow x=109\)
Vậy \(x\in\left\{-81;109\right\}\)
c) \(\left|2x+3\right|=4\)
TH1 : \(2x+3=4\)
\(\Leftrightarrow2x=1\)
\(\Leftrightarrow x=\frac{1}{2}\)
TH2 : \(2x+3=-4\)
\(\Leftrightarrow2x=-7\)
\(\Leftrightarrow x=-\frac{7}{2}\)
Vậy \(x\in\left\{\frac{1}{2};-\frac{7}{2}\right\}\)
a/ x-2+7=-27
x-2=-34
x=-32
b/ Đề bị điên ak?
c/ -2x=2
x=-1
d/ ko hỉu đề
a) 3/7 + 4/9 + 4/7 + 5/9
= ( 3/7 + 4/7 ) + ( 4/9 + 5/9 )
= 7/7 + 9/9
= 1 + 1
= 2
b)1/5 + 4/10 + 9/15 + 16/20 + 25/25 + 36/30 + 49/35 + 64/40 + 81/45
= 1/5 + 2/5 + 3/5 + 4/5 + 5/5 + 6/5 + 7/5 + 8/5 + 9/5
= ( 1/5 + 9/5 ) + ( 2/5 + 8/5 ) + (7/5 + 3/5 ) + ( 4/5 + 6/5 ) + 5/5
= 2 + 2 + 2 + 2 + 1
= 2 x 4 + 1
= 8 +1
= 9
c) 1/8 + 1/12 + 3/8 + 5/12
= ( 1/8 + 3/8 ) + ( 1/12 + 5/12)
= 4/8 + 6/12
= 1/2 + 1/2
= 2/4 = 1/2
mỏi tay rồi
d; (1 - \(\dfrac{1}{2}\)) x (1 - \(\dfrac{1}{3}\)) x (1 - \(\dfrac{1}{4}\)) x ... x ( 1 - \(\dfrac{1}{100}\))
= \(\dfrac{1}{2}\) x \(\dfrac{2}{3}\) x \(\dfrac{3}{4}\) x \(\dfrac{3}{4}\) x ... x \(\dfrac{99}{100}\)
= \(\dfrac{1}{100}\)
a, \(\left|x+2\right|-12=-1\)
\(\Leftrightarrow\left|x+2\right|=11\)
\(\Leftrightarrow\orbr{\begin{cases}x+2=11\\x+2=-11\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=9\\x=-13\end{cases}}\)
d, ( x - 2 ) - ( - 8 ) = - 137
( x - 2 ) + 8 = - 137
x - 2 = -137 - 8
x - 2 = - 145
x = - 145 + 2
x = - 143
Phần b;c bn làm giống phần a nha