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a)30-2(3+x)=14
2(3+x)=30-14
2(3+x)=16
3+x =16:2
3+x =8
x =8-3
x =5
b)15-3(10-x)=9
3(10-x)=15-9
3(10-x)=6
10-x=6:3
10-x=2
x=10-2
x=8
c)16-4(2x-9)=8
4(2x-9)=16-8
4(2x-9)=8
2x-9=8:4
2x-9=2
2x=2+9
2x=11
x= 11:2
x=5,5
cho mk 1 nha
\(a,\Rightarrow x=3\)
\(b,\Rightarrow2x-1=2\)
\(\Rightarrow2x=3\)
\(\Rightarrow x=\dfrac{3}{2}\)
\(c,\Rightarrow x-2=4\)
\(\Rightarrow x=6\)
\(d,\Rightarrow2x-3=3\)
\(\Rightarrow2x=6\)
\(\Rightarrow x=3\)
\(a,\Rightarrow x=3\\ b,\Rightarrow2x-1=2\Rightarrow x=\dfrac{3}{2}\\ c,\Rightarrow\left[{}\begin{matrix}x-2=4\\x-2=-4\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=6\\x=-2\end{matrix}\right.\\ d,\Rightarrow\left[{}\begin{matrix}2x-3=3\\2x-3=-3\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=3\\x=0\end{matrix}\right.\\ e,\Rightarrow2x+5=3^2=9\Rightarrow x=2\)
a)
200 - ( 2 . x + 6 ) = 8 . 2
200 - ( 2 . x + 6 ) = 16
2 . x + 6 = 200 - 16
2 . x + 6 = 184
x + 6 = 184 : 2
x + 6 = 92
x = 92 - 6
x = 86
b)
2 . x : 4 = 16
x : 4 = 16 : 2
x : 4 = 8
x = 8 . 4
x = 32
c)
2008 . x : 2008 . 5 = 2008 . 3
2008. ( x : 5 ) = 6024
x : 5 = 6024 : 2008
x : 5 = 3
x = 3 . 5
x = 15
Giải:
a) \(\dfrac{-5}{6}-x=\dfrac{7}{12}+\dfrac{-1}{3}\)
\(\dfrac{-5}{6}-x=\dfrac{1}{4}\)
\(x=\dfrac{-5}{6}-\dfrac{1}{4}\)
\(x=\dfrac{-13}{12}\)
b) \(2.\left(x-\dfrac{1}{3}\right)=\left(\dfrac{1}{3}\right)^2+\dfrac{5}{9}\)
\(2.\left(x-\dfrac{1}{3}\right)=\dfrac{1}{9}+\dfrac{5}{9}\)
\(2.\left(x-\dfrac{1}{3}\right)=\dfrac{2}{3}\)
\(x-\dfrac{1}{3}=\dfrac{2}{3}:2\)
\(x-\dfrac{1}{3}=\dfrac{1}{3}\)
\(x=\dfrac{1}{3}+\dfrac{1}{3}\)
\(x=\dfrac{2}{3}\)
c) \(\left|2x-\dfrac{3}{4}\right|-\dfrac{3}{8}=\dfrac{1}{8}\)
\(\left|2x-\dfrac{3}{4}\right|=\dfrac{1}{8}+\dfrac{3}{8}\)
\(\left|2x-\dfrac{3}{4}\right|=\dfrac{1}{2}\)
\(\Rightarrow\left[{}\begin{matrix}2x-\dfrac{3}{4}=\dfrac{1}{2}\\2x-\dfrac{3}{4}=\dfrac{-1}{2}\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{5}{8}\\x=\dfrac{1}{8}\end{matrix}\right.\)
d) \(\dfrac{2}{3}x+\dfrac{1}{6}x=3\dfrac{5}{8}\)
\(x.\left(\dfrac{2}{3}+\dfrac{1}{6}\right)=\dfrac{29}{8}\)
\(x.\dfrac{5}{6}=\dfrac{29}{8}\)
\(x=\dfrac{29}{8}:\dfrac{5}{6}\)
\(x=\dfrac{87}{20}\)
Bài 1 :
a) 72x-1 = 343
=> 72x-1 = 73
=> 2x - 1 = 3 => 2x = 4 => x = 2
b) (7x - 11)3 = 25.32 + 200
=> (7x - 11)3 = 32.9 + 200
=> (7x - 11)3 = 488
xem kĩ lại đề này :vvv
c) 174 - (2x - 1)2 = 53
=> (2x - 1)2 = 174 - 53
=> (2x - 1)2 = 174 - 125 = 49
=> (2x - 1)2 = (\(\pm\)7)2
=> \(\orbr{\begin{cases}2x-1=7\\2x-1=-7\end{cases}}\Rightarrow\orbr{\begin{cases}x=4\\x=-3\end{cases}}\)
Mà x \(\in\)N nên x = 4( thỏa mãn điều kiện)
Bài 2 :
a) x5 = 32 => x5 = 25 => x = 2
b) (x + 2)3 = 27
=> (x + 2)3 = 33
=> x + 2 = 3 => x = 3 - 2 = 1
c) (x - 1)4 = 16
=> (x - 1)4 = 24
=> x - 1 = 2 => x = 3 ( vì đề bài cho x thuộc N nên thỏa mãn)
d) (x - 1)8 = (x - 1)6
=> (x - 1)8 - (x - 1)6 = 0
=> (x - 1)6 [(x - 1)2 - 1] = 0
=> \(\orbr{\begin{cases}\left(x-1\right)^6=0\\\left(x-1\right)^2-1=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=1\\\left(x-1\right)^2=1\end{cases}}\Rightarrow\orbr{\begin{cases}x=1\\\left(x-1\right)^2=\left(\pm1\right)^2\end{cases}}\)
+) x - 1 = 1 => x = 2 ( tm)
+) x - 1 = -1 => x = 0 ( tm)
Vậy x = 1,x = 2,x = 0
a). 3. |9 - 2x| - 17 = 16
3. |9 - 2x| = 16 + 17
3. |9 - 2x| = 33
|9 - 2x| = 33 : 3
|9 - 2x| = 11
=> 9 - 2x = 11
2x = 9 - 11
2x = -2
x = - 2 : 2
x = - 1
hay 9 - 2x = - 11
2x = 9 - (- 11)
2x = 9 + 11
2x = 20
x = 20 : 2
x = 10
Vậy x = -1; x = 10
a) 3.| 9 - 2x | -17 = 16
3. | 9 - 2x | = 16 + 17 = 33
| 9 - 2x | = 33 : 3 = 11
\(\Rightarrow\)9 - 2x = 11 hoặc 9 - 2x = -11
2x = 9 - 11 2x = 9 - ( - 11 )
2x = -2 2x = 20
x = -2 : 2 x = 20 : 2
x = -1 x = 10
1a) x - 7 = -18
=> x = -18 + 7
=> x = -11
b) -2x + 8 = -24
=> -2x = -24 - 8
=> -2x = -32
=> x = -32 : (-2)
=> x = 16
c) 4 - 2x = 59
=> 2x = 4 - 59
=> 2x = -55
=> x = -55 : 2
=> x = -27,5
d) -36 - x = 59
=> x = -36 - 59
=> x = -95
k) -81 : x = (-3)
=> x = -81 : (-3)
=> x = 27
g) -16 : x = 2
=> x = -16 : 2
=> x = -8
m) (6 - 27) - (3 - x) = (-7) . (-8)
=> -21 - (3 - x) = 56
=> 3 - x = -21 - 56
=> 3 - x = -77
=> x = 3 + 77
=> x = 80
ta có: