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nhiều lắm rồi

\(x\left(x-2\right)+x-2=0\\ \Leftrightarrow x\left(x-2\right)+\left(x-2\right)=0\\ \Leftrightarrow\left(x-2\right)\left(x+1\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x-2=0\\x+1=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=2\\x=-1\end{matrix}\right.\)

\(x^2-2x+1=9\\ \Leftrightarrow\left(x-1\right)^2=9\\ \Leftrightarrow\left[{}\begin{matrix}x-1=-3\\x-1=3\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=-2\\x=4\end{matrix}\right.\)

\(7x^2=2x\\ \Leftrightarrow7x^2-2x=0\\ \Leftrightarrow x\left(7x-2\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=0\\7x-2=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=0\\x=\dfrac{2}{7}\end{matrix}\right.\)

\(x^2-6x=8\\ \Leftrightarrow x^2-6x-8=0\\ \left(x^2-6x+9\right)-17=0\\ \Leftrightarrow\left(x-3\right)^2-\sqrt{17^2}=0\\ \Leftrightarrow\left(x-3-\sqrt{17}\right)\left(x-3+\sqrt{17}\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x-3-\sqrt{17}=0\\x-3+\sqrt{17}=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=3+\sqrt{17}\\x=3-\sqrt{17}\end{matrix}\right.\)

a) 1/7 - 3/5x = 3/5

3/5x= 1/7 - 3/5 

3/5x = -16/35

x= -16/35 : 3/5 = -16/21

b) 3/7 - 1/2x = 5/3

1/2x = 3/7 - 5/3 = -26/21

x= -26/21 : 1/2 = -52/21

 Thanh Nga làm nốt đc ko bn

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

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

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

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

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

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

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

cảm ơn bạn

bài 1)
a) \(\dfrac{\left(-3\right)^{10}.15^5}{25^3.\left(-9\right)^7}\)

\(=\dfrac{\left(-3\right)^{10}.\left(3.5\right)^5}{\left(5^2\right)^3.\left(-3.3\right)^7}\)

\(=\dfrac{\left(-3\right)^{10}.3^5.5^5}{5^6.\left(-3\right)^7.3^7}\)

\(=\dfrac{\left(-3\right)^3.1.1}{5.1.3^2}\)

\(=\dfrac{-27.1.1}{5.1.9}\)

\(=\dfrac{-27}{45}\)

\(=\dfrac{-9}{15}\)

b)\(2^3+3.\left(\dfrac{1}{9}\right)^0-2^{-2}.4\left[\left(-2\right)^2:\dfrac{1}{2}\right].8\)

\(=8+3.1-\dfrac{1}{2^2}.4+\left[\left(4:\dfrac{1}{2}\right)\right].8\)

\(=8+3.1-\dfrac{1}{4}.4+\left[4.\dfrac{2}{1}\right].8\)

\(=8+3.1-\dfrac{1}{4}.4+8.8\)

\(=8+3-1+64\)

\(=11-1+64\)

\(=10+64\)

\(=74\)

\(4\left(x-2\right)+10=5-3x\)

\(\Rightarrow4x-8+10=5-3x\)

\(\Rightarrow4x+3x=5-10+8\)

\(\Rightarrow7x=3\)

\(\Rightarrow x=\frac{3}{7}\)

\(4x-8-10=7-x\)

\(\Rightarrow4x+x=7+10+8\)

\(\Rightarrow5x=25\)

\(\Rightarrow x=5\)

\(\left|2x-1\right|=3\)

\(\Leftrightarrow\orbr{\begin{cases}2x-1=3\\2x-1=-3\end{cases}\Leftrightarrow\orbr{\begin{cases}x=2\\x=-1\end{cases}}}\)

\(\left|1-2x\right|=5\)

\(\Leftrightarrow\orbr{\begin{cases}1-2x=5\\1-2x=-5\end{cases}\Leftrightarrow\orbr{\begin{cases}x=-2\\x=3\end{cases}}}\)

\(\left|4+x\right|=10\)

\(\Leftrightarrow\orbr{\begin{cases}4+x=10\\4+x=-10\end{cases}\Leftrightarrow\orbr{\begin{cases}x=6\\x=-14\end{cases}}}\)

2x + 1/2 = -5/3

2x = -13/6

x = -13/12

2x + ½ = -5/3

       2x = -5/3 - 1/2

       2x = -13/6

         x = -13/6 : 2

         x = -13/12

1/7 - 3/5 x = 3/5

       -3/5 x = 3/5 - 1/7

       -3/5 x = 16/35

              x = 16/35 : -3/5

              x = -16/21

-3x - ¾ = 5/6

      -3x = 5/6 + 3/4

      -3x = 19/12

         x = 19/12 : (-3)

         x = -19/36

3/7 - 1/2 x = 5/3

       -1/2 x = 5/3 - 3/7

       -1/2 x = 26/21

              x = 26/21 : (-1/2)

              x = -52/21

2x - ¾ = 5/8

      2x = 5/8 + 3/4

      2x = 11/8

        x = 11/8:2

        x = 11/16

¼ x - |-7/5| = -5/3

   ¼ x - 7/5 = -5/3

           ¼ x = -5/7 + 7/5

           ¼ x = 24/35

               x = 24/35 : 1/4

              x = 96/35

\(9^{10}-3^{18}\\ =\left(3^2\right)^{10}-3^{18}=3^{20}-3^{18}\\ =3^{18}\left(3^2-1\right)\\ =3^{18}\left(9-1\right)\\ =3^{18}.8⋮8\)

11/4=22/8

6/8=6/8

11/4=22/8

6/8 giữ nguyên

11/4 và 3/4