a/ \(3^{x-1}=27\)

\(\Leftrightarrow3^{x-1}=3^3\)

\(\Leftrightarrow x-1=3\)

\(\Leftrightarrow x=2\)

Vậy..

b/ \(12+2x=2^2+5^2\)

\(\Leftrightarrow12+2x=29\)

\(\Leftrightarrow2x=17\)

\(\Leftrightarrow x=\frac{17}{2}\)

Vậy ...

ý b mình nhầm nhé

\(12+2x=2^2.5^2\)

\(\Leftrightarrow12+2x=100\)

\(\Leftrightarrow2x=88\)

\(\Leftrightarrow x=44\)

Vậy ...

\(x\left(x-1\right)\left(x+2\right)=0\)

\(\Leftrightarrow\hept{\begin{cases}x=0\\x-1=0\\x+2=0\end{cases}}\) \(\Leftrightarrow\hept{\begin{cases}x=0\\x=1\\x=-2\end{cases}}\)

Đổi dấu ngoặc nhọn thành ngoặc vuông giúp mính nhé :333

\(\frac{1}{4}+\frac{1}{3}:\left(2x-1\right)=\) \(-5\)

\(\frac{1}{3}:\left(2x-1\right)=\frac{-21}{4}\)

\(2x-1=\frac{-4}{63}\)

\(2x=\frac{59}{63}\)

\(x=\frac{59}{126}\)

\(-\frac{1}{10}< =x< =\frac{3}{5}\) 

\(\frac{-4}{9}< x< =\frac{2}{3}\)

Đoàn Thị Thanh Ngân viết lời giải hộ thanks

\(\left(2x+1\right)-\left(x+\frac{1}{3}\right)=4\)

\(\Leftrightarrow\left(2x-x\right)+\left(1-\frac{1}{3}\right)=4\)

\(\Leftrightarrow x+\frac{2}{3}=4\)

\(\Leftrightarrow x=\frac{10}{3}\)

(2x+1)-(x+1/3)=4

<=> 2x+1-x-1/3=4

<=> (2x-x) + (1-1/3)=4

<=> x+2/3=4

<=> x=4-2/3

<=> x=10/3

Trả lời

\(5^3\cdot5^6=5^{3+6}=5^9\)

hok tốt 

==.==

 giúp mk nhé

Để \(A\in Z\) thì :

\(x+2⋮3x-1\)

Mà \(3x-1⋮3x-1\)

\(\Leftrightarrow\hept{\begin{cases}3x+6⋮3x-1\\3x-1⋮3x-1\end{cases}}\)

\(\Leftrightarrow7⋮3x-1\)

\(\Leftrightarrow3x-1\inƯ\left(7\right)\)

Suy ra :

+) \(3x-1=1\Leftrightarrow x=\frac{2}{3}\)

+) \(3x-1=7\Leftrightarrow x=\frac{8}{3}\)

+) \(3x-1=-1\Leftrightarrow x=0\)

+) \(3x-1=-7\Leftrightarrow x=-2\)

\(\left\{\left[\left(10-x\right)\cdot2-1\right]:2+7\right\}\cdot2=24\)

\(\left[\left(10-x\right)\cdot2-1\right]:3+7=\frac{24}{2}=12\)

\(\left[\left(10-x\right)\cdot2-1\right]:3=12-7=5\)

\(\left(10-x\right)\cdot2-1=5\cdot3=15\)

\(\left(10-x\right)\cdot2=15+1=16\)

\(10-x=\frac{16}{2}=8\)

\(x=10-8\)

\(\Rightarrow x=2\)

Vậy ...

{ [ ( 10 - x ) . 2 - 1 ] : 3 + 7 } . 2 = 24

[ ( 10 - x ) . 2 - 1 ] : 3 + 7 = 24 : 2

[ ( 10 - x ) . 2 - 1 ] : 3 + 7 = 12

[ ( 10 - x ) . 2 -1 ] : 3 = 12 - 7

[ ( 10 -x ) . 2 - 1 ] : 3 = 5

( 10 - x ) . 2 - 1 = 5 . 3

( 10 - x ) . 2 - 1 = 15

( 10 - x ) . 2 = 15 + 1

( 10 - x ) . 2 = 16

10 - x = 16 : 2

10 - x = 8

x = 10 - 8

x = 2

Vậy x = 2

chúc bn hok tốt

Ta có : x(x + 1) = 0 

\(\Leftrightarrow\orbr{\begin{cases}x=0\\x+1=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=0\\x=-1\end{cases}}}\)

Ta có : \(x^2+4x=0\)

\(\Leftrightarrow x\left(x+4\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}x=0\\x+4=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=0\\x=-4\end{cases}}}\)

a) \(\orbr{\begin{cases}x=0\\x+1=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=0\\x=-1\end{cases}}}\)

b) \(x\left(x+4\right)=0\Leftrightarrow\orbr{\begin{cases}x=0\\x+4=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=0\\x=-4\end{cases}}\)