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a) \(6-2x-8=-4\Leftrightarrow2x=2\Leftrightarrow x=1\)
b) \(6⋮x\Rightarrow x=\left\{-6;-3;-2;-1;1;2;3;6\right\}\)
c) \(2x-3=-7\Leftrightarrow2x=-4\Leftrightarrow x=-2\)
d) \(231-x+6=103\Leftrightarrow x=124\)
e) hình như sai đề
f) \(x^3=27\Leftrightarrow x=3\)
g) \(x+2=3\Leftrightarrow x=1\)
h) \(\left(x+5\right)^2=25\Leftrightarrow x+5=5\Leftrightarrow x=0\)
i) \(x^2=9\Leftrightarrow\orbr{\begin{cases}x=-3\\x=3\end{cases}}\)
j) \(14⋮\left(x+3\right)\Rightarrow x=\left\{-17;-10;-5;-4;-2;4;11\right\}\)
a) 124 + (118 - x) = 217
118 - x = 217 - 124
118 - x = 93
x = 118 - 93
x = 25
b) 156 - (x + 61) = 82
x + 61 = 156 - 82
x + 61 = 74
x = 74 - 61
x = 13
c) 219 - 7(x + 1) = 100
7(x + 1) = 219 - 100
7(x + 1) = 119
x + 1 = 119 : 7
x + 1 = 17
x = 17 - 1
x = 16
d) (3x - 6).3 = 3⁴
3x - 6 = 3⁴ : 3
3x - 6 = 3³
3x - 6 = 27
3x = 27 + 6
3x = 33
x = 33 : 3
x = 11
e) 231 - (x - 6) = 1339 : 13
231 - (x - 6) = 103
x - 6 = 231 - 103
x - 6 = 128
x = 128 + 6
x = 134
a) 124 + (118 - x) = 217
118 - x = 217 - 124
118 - x = 93
x = 118 - 93
x = 25
b) 156 - (x + 61) = 82
x + 61 = 156 - 82
x + 61 = 74
x = 74 - 61
x = 13
c) 219 - 7(x + 1) = 100
7(x + 1) = 219 - 100
7(x + 1) = 119
x + 1 = 119 : 7
x + 1 = 17
x = 17 - 1
x = 16
d) (3x - 6) . 3 = 34
(3x - 6) . 3 = 81
(3x - 6) = 81 : 3
(3x - 6) = 27
3x = 27 + 6
3x = 33
x = 33 : 3
x = 11
e) 231 - (x - 6) = 1339 : 13
231 - (x - 6) = 103
(x - 6) = 231 - 103
x - 6 = 128
x = 128 + 6
x = 134
a) \(6-2\left(x+4\right)=-4\)
\(\Leftrightarrow6-2x-8=-4\)
\(\Leftrightarrow-2-2x=-4\)
\(\Leftrightarrow-2x=-4+2\)
\(\Leftrightarrow-2x=-2\)
\(\Leftrightarrow x=1\)
Vậy \(x=1\)
b) tự làm.
c) \(2x-15:5=-7\)
\(\Leftrightarrow2x-7,5=-7\)
\(\Leftrightarrow2x=-7+7,5\)
\(\Leftrightarrow2x=0,5\)
\(\Leftrightarrow x=0,25\)
\(\Leftrightarrow x=\dfrac{1}{4}\)
Vậy \(x=\dfrac{1}{4}\)
d) \(231-\left(x-6\right)=1339:13\)
\(\Leftrightarrow231-x+6=103\)
\(\Leftrightarrow237-x=103\)
\(\Leftrightarrow237-x+6=103\)
\(\Leftrightarrow-x=103-237\)
\(\Leftrightarrow-x=-134\)
\(\Leftrightarrow x=134\)
e) đề j mà có 2 dấu bằng >> sai :v
f) \(28-x^3=1\)
\(\Leftrightarrow-x^3=1-28\)
\(\Leftrightarrow-x^3=-27\)
\(\Leftrightarrow x^3=27\)
\(\Leftrightarrow x^3=3^3\)
\(\Leftrightarrow x=3\)
Vậy \(x=3\)
g) \(\left(x+2\right)^3=27\)
\(\Leftrightarrow\left(x+2\right)^3=3^3\)
\(\Leftrightarrow x+2=3\)
\(\Leftrightarrow x=3-2\)
\(\Leftrightarrow x=1\)
Vậy \(x=1\)
h) \(81-\left(x-5\right)^2=56\)
\(\Leftrightarrow-\left(x-5\right)^2=56-81\)
\(\Leftrightarrow-\left(x-5\right)^2=-25\)
\(\Leftrightarrow\left(x-5\right)^2=25\)
\(\Leftrightarrow x-5=\pm5\)
\(\Leftrightarrow\left[{}\begin{matrix}x-5=5\\x-5=-5\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=5+5\\x=-5+5\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=10\\x=0\end{matrix}\right.\)
Vậy \(x_1=0;x_2=10\)
j) \(x^2=9\)
\(\Leftrightarrow x=\pm3\)
\(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=-3\end{matrix}\right.\)
Vậy \(x_1=-3;x_2=3\)
l) tự làm.
\(a.2.x-138=2^3.3^2\)
\(2.x-138=8.9\)
\(2.x-138=72\)
\(2.x\) \(=72+138\)
\(2.x\) \(=210\)
\(x\) \(=210:2\)
\(x\) \(=105\)
\(b.231-\left(x-6\right)=1339:13\)
\(231-\left(x-6\right)=103\)
\(x-6=231-103\)
\(x-6=128\)
\(x\) \(=128+6\)
\(x\) \(=134\)
\(c.\left[\left(6.x-72\right):2-84\right].28=5628\)
\(\left[\left(6.x-72\right):2-84\right]\) \(=5628:28\)
\(\left(6.x-72\right):2-84\) \(=201\)
\(\left(6.x-72\right):2\) \(=201-84\)
\(\left(6.x-72\right):2\) \(=117\)
\(6.x-72\) \(=117.2\)
\(6.x-72\) \(=234\)
\(6.x\) \(=234+72\)
\(6.x\) \(=306\)
\(x\) \(=306:6\)
\(x\) \(=51\)
mik nè
a) 10 + 2x = 16.4 : 4
=> 10 + 2x = 16
2x = 16 - 10
2x = 6
x = 6:2 = 3
b) 231 - ( x - 6 ) = 1339 : 13
=> 231 - ( x - 6 ) = 103
( x - 6 ) = 231 - 103
x - 6 = 128
x = 128 + 6
x = 134
a: =>2x+10=4^2=16
=>2x=6
=>x=3
b: =>2x-138=8*9=72
=>2x=138+72=210
=>x=105
c: =>231-(x-6)=103
=>x-6=128
=>x=134
\(a.10+2x=4^5:4^3\\ \Leftrightarrow10+2x=4^2\\ \Leftrightarrow2x=6\\ \Leftrightarrow x=3\)
\(b.2x-138=2^3.3^2\\ \Leftrightarrow2x-138=72\\ \Leftrightarrow x=210:2\\ \Leftrightarrow x=105\)
\(c.231-\left(x-6\right)=1339:13\\ \Leftrightarrow231-\left(x-6\right)=103\\ \Leftrightarrow x-6=128\\ \Leftrightarrow x=134\)
Chú ý : Nếu bạn chưa học \(\Leftrightarrow\) thì bạn bỏ đi nha !
a,2x-138=72 231-(x-6)=103
x-6 =231-103
2x =72+138 x-6 =128
2x =210 x =128+6
x =210/2 x =134
x =105
a)13-2(x+1)=7
2.(x+1)=13-7
2.(x+1)=6
x+1=6/2
x+1=3
x=3-1
x=2
a, 13 - 2 ( x + 1 ) = 7
2 .( x + 1 ) = 13 - 7
2 .( x + 1 ) = 6
x + 1 = 6 : 2
x + 1 = 3
x = 3 - 1
x = 4
a)0,12.X-2=4
=>0,12.X=4+2
=>0,12.X=6
=>X=6:0,12
=>X=50
b)231-(X-6)=1339:13
=>231-(X-6)=103
=>X-6=231-103
=>X-6=128
=>X=128+6
=>X=134
c)7,99.X+X.2+X:100=7,9
=>X.(7,99+2+1/100)=7,9
=>X.10=7,9
=>X=7,9:10
=>X=0,79
d)(14-X:6).7=84
=>14-X:6=84:7
=>14-X:6=12
=>X:6=14-12
=>X:6=2
=>X=2.6
=>X=12