Tìm x
a) 2x+1 +54 =86
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Ta có : 3(2x - 4) + 11 = -11
=> 3(2x - 4) = 0
Mà 3 khác 0
Nên : 2x - 4 = 0
=> 2x = 4
=> x = 2
a,\(\left(x-15\right):50+22=24\)
\(< =>\frac{\left(x-15\right)}{50}=2< =>x-15=100\)
\(< =>x=100+15=115\)
b,\(42-\left(2x+32\right)+12:2=6\)
\(< =>42-2x-32=0\)
\(< =>10-2x=0< =>x=\frac{10}{2}=5\)
Làm nốt :
c) \(134-2\left\{156-6\cdot\left[54-2\cdot\left(9+6\right)\right]\right\}\cdot x=86\)
=> 134 - 2{156 - 6 . [54 - 2 . 15]} . x = 86
=> 134 - 2{156 - 6 . [54 - 30]} . x = 86
=> 134 - 2{156 - 6. 24} . x = 86
=> 134 - 2{156 - 144} . x = 86
=> 134 - 2.12 . x = 86
=> 134 - 24 . x = 86
=> 24.x = 48
=> x = 2
Bài 2 : a) 120 : [21 - (4x - 4)] = 23.3
=> 120 : [21 - (4x - 4)] = 8.3
=> 120 : [21 - (4x - 4)] = 24
=> 21 - (4x - 4) = 5
=> 4x - 4 = 16
=> 4x = 20
=> x = 5
b) 3.[205 - (x - 9)] - 486 = 0
=> 3.[205 - (x - 9)] = 486
=> 205 - (x - 9) = 162
=> x - 9 = 205 - 162 = 43
=> x = 43 + 9 = 52
c) 204 - 2{200 - 5.[64 - 2.(11 + 6)]} . x = 4
=> 204 - 2{200 - 5.[64 - 2.17]} . x = 4
=> 204 - 2{200 - 5 .[64 - 34]}.x = 4
=> 204 - 2{200 - 5.30} . x = 4
=> 204 - 2{200 - 150}.x = 4
=> 204 - 2.50 . x = 4
=> 2.50.x = 200
=> 100.x = 200
=> x = 2
Câu 1: \(20⋮x\)=> \(x\inƯ\left(20\right)=\left\{\pm1;\pm2;\pm4;\pm5;\pm10;\pm20\right\}\)
Câu 2: 2x + 9 = 2019
2x = 2019 - 9
2x = 2010
x = 2010 : 2
x = 1005
Câu 3: 6x - 39 = 5628 : 28
6x - 39 = 201
6x = 201 +39
6x = 240
x = 240 : 6
x = 40
Câu 4: 2x+1 + 54 = 86
2x+1 = 86 - 54 = 32
2x+1 = 25
=>x+1 = 5
=>x=4
42 -(2x + 32) + 12 :2 =6
42 - 2x - 32 + 6 = 6
42 - 2x - 32 = 0
42 - 2x = 32
2x = 42 - 32 = 10
x = 5
134 - 2 . {156 - 6.[54 -2.(9+6) ] } x = 86
134 - 2.{ 156 - 6.[54 - 2 . 15 ]} x = 86
134 - 2.{ 156 - 6 . 24} x = 86
134 - 2. 12 .x = 86
134 - 24x = 86
24x = 48
x = 2
\(42-\left(2x+32\right)+12:2=6\)
\(\Rightarrow42-2x-32=0\)
\(\Rightarrow2x=10\)
\(\Rightarrow x=5\)
134 - 2 . {156 - 6[54 - 2(9 + 6)]} . x = 86
134 - 2 . { 156 - 6 [ 54 - 2 . 15 ) ] } . x = 86
134 - 2 . { 156 - 6 [ 54 - 30 ] } . x = 86
134 - 2 . { 156 - 6 . 24 } . x = 86
134 - 2 . { 156 - 144 } . x = 86
134 - 2 . 21 . x = 86
2 . 21 . x = 134 - 86
2 . 21 . x = 48
21 . x = 48 : 2
21 . x = 24
x = 24 : 21
x = 1
12x-10x+54=86
(12-10)x+54=86
2x+54=86
2x=86-54
2x=32
x=32:2
x=16
a: \(\left(x+1\right)^3+\left(x-2\right)^3=2x^3+2\left(2x-1\right)^2-9\)
\(\Leftrightarrow x^3+3x^2+3x+1+x^3-6x^2+12x-8=2x^3+2\left(4x^2-4x+1\right)-9\)
\(\Leftrightarrow2x^3-3x^2+15x-7=2x^3+8x^2-8x-7\)
\(\Leftrightarrow-11x^2+23x=0\)
\(\Leftrightarrow x\left(-11x+23\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=\dfrac{23}{11}\end{matrix}\right.\)
\(2^{x+1}+54=86\)
\(\Leftrightarrow2^{x+1}=32\)
\(\Leftrightarrow2^{x+1}=2^5\)
\(\Leftrightarrow x+1=5\)
\(\Leftrightarrow x=4\)
a) 2x+1 + 54 = 86
=> 2x+1 = 86 - 54
=> 2x+1 = 32
=> 2x+1 = 25
=> x + 1 = 5
=> x = 5 - 1
=> x = 4
Vậy x = 4