\(a,\Rightarrow\dfrac{\left(-3\right)^x}{\left(-3\right)^4}=\left(-3\right)^3\\ \Rightarrow\left(-3\right)^{x-4}=\left(-3\right)^3\\ \Rightarrow x-4=3\Rightarrow x=7\\ b,Sửa:\left(x-\dfrac{1}{2}\right)^2=25\Rightarrow\left[{}\begin{matrix}x-\dfrac{1}{2}=5\\x-\dfrac{1}{2}=-5\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\dfrac{11}{5}\\x=-\dfrac{9}{5}\end{matrix}\right.\)

34200

Giá 1 gói kẹo : 285000 : 5 = 57000 đ
Giá 6 gói kẹo : 57000 x 6 = 342000 đ
        ĐS :  342000 đ

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giá 1 gói kẹo  : 285000 : 5 = 57000 đ

giá 6 gói kẹo : 57000 x 6 = 342000 đ
       Đs: 342000 đ

\(\Rightarrow\left[{}\begin{matrix}2x-3=5\\2x-3=-5\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=4\\x=-1\end{matrix}\right.\)

\(2^{x+1}=4^7:8^3\\ \Rightarrow2^{x+1}=2^{14}:2^9\\ \Rightarrow2^{x+1}=2^5\\ \Rightarrow x+1=5\\\Rightarrow x=4\)

4(2x + 7) - 3(3x - 2) = 24

8x + 28 - 9x + 6 = 24

-x + 34 = 24

-x = 24 - 34

-x = -10

x = 10

=>  8x +28 -9x+6=24

=>-x=24-6-28

=>-x=-10

=> x=10

  study well

 k nha

 ai k cho mk mk trả lại gấp đôi

=>8x+28-9x+6=24

-x=24-6-28

-x=-10

=>x=10

\(\frac{2}{3}\left(x-1\right)+\frac{4}{7}\left(2x-3\right)=\frac{1}{21}\left(x-6\right)\)

\(\frac{2}{3}x-\frac{2}{3}+\frac{8}{7}x-\frac{12}{7}=\frac{1}{21}x-\frac{6}{21}\)

\(\frac{2}{3}x+\frac{8}{7}x-\frac{1}{21}x=\frac{2}{3}+\frac{12}{7}-\frac{6}{21}\)

\(\frac{14}{21}x+\frac{24}{21}x-\frac{1}{21}x=\frac{14}{21}+\frac{36}{21}-\frac{6}{21}\)

\(x\left(\frac{14}{21}+\frac{24}{21}-\frac{1}{21}\right)=\frac{14+36-6}{21}\)

\(\frac{37}{21}x=\frac{44}{21}\)

\(x=\frac{44}{21}:\frac{37}{21}=\frac{44}{37}\)

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