|2.x+4|=6

TH1: 2.x+4 = 6                

x = 1

TH2: 2.x+4 = - 6                

x = -5

Vậy x thuộc 1 và -5

|2-3.x|=5

Th1: 2-3.x=5

x = -1

Th2: 2-3.x= -5

x = 7/3

Vậy x thuộc -1 và 7/3

|7-x|=9

TH1: 7-x =9

x = -2

TH2: 7-x = -9

x = 16

Vậy.........

a) Ta có: \(\left|2x+4\right|=6\)

\(\Leftrightarrow\left[{}\begin{matrix}2x+4=6\\2x+4=-6\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}2x=6-4=2\\2x=-6-4=-10\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=1\\x=-5\end{matrix}\right.\)

Vậy: \(x\in\left\{1;-5\right\}\)

b) Ta có: \(\left|2-3x\right|=5\)

\(\Leftrightarrow\left[{}\begin{matrix}2-3x=5\\2-3x=-5\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}-3x=3\\-3x=-7\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-1\\x=\dfrac{7}{3}\end{matrix}\right.\)

Vậy: \(x\in\left\{-1;\dfrac{7}{3}\right\}\)

c) Ta có: \(\left|7-x\right|=9\)

\(\Leftrightarrow\left[{}\begin{matrix}7-x=9\\7-x=-9\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}-x=2\\-x=-16\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-2\\x=16\end{matrix}\right.\)

Vậy: \(x\in\left\{-2;16\right\}\)

a. |2x + 4| = 6

2x + 4 = 6 hoặc 2x + 4 = -6

2x      = 6 - 4 hoặc 2x   = -6 - 4

2x    = 2 hoặc 2x   = -10 

x     = 2 : 2 hoặc x = -10 : 2

x = 1 hoặc x = -5

Vậy x = 1 hoặc x = -5

|2 - 3x| = 5

2 - 3x = 5 hoặc 2 - 3x = -5

3x  = 2 - 5 hoặc 3x   = -5 - 2

3x = -3 hoặc 3x = -7

x = -3 : 3 hoặc  x = -7 : 3 (ko tính được)

x = -1 

Vậy x = -1

c. |7 - x| = 9

7 - x = 9 hoặc 7 - x = -9

x   = 7 - 9 hoặc x  = 7 - (-9)

x = -2 hoặc x = 16 

Vậy x = -2 hoặc x = 16

y=8/9x4/7=32/63

y=8/9x4/7

y=32/63

x/y = 2/5 ⇒ x/2 = y/5

⇒ x/5 = 2y/10

Áp dụng tính chất của dãy tỉ số bằng nhau, ta có:

x/2 = 2y/10 = (x + 2y)/(2 + 10) = 36/12 = 3

x/2 = 3 ⇒ x = 2 . 3 = 6

y/5 = 3 ⇒ y = 5 . 3 = 15

Vậy x = 6; y = 10

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

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

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

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

a) 12² + ( 518 - x ) = -36

144 + ( 518 - x ) = -36

158 - x = -36 - 144

158 - x = -180

x = 158 - (-180)

x = 338

b) 2 ( x - 5 ) = 8

x - 5 = 8 : 2

x - 5 = 4

x = 4 + 5

x = 9

a) \(12^2+\left(518-x\right)=-36\)

\(144+518-x=-36\)

\(662-x=-36\)

\(x=662+36\)

\(x=698\)

vậy \(x=698\)

b) \(2\left(x-5\right)=8\)

\(x-5=4\)

\(x=9\)

vậy \(x=9\)

\(a,12^2+\left(518-x\right)=-36\)

\(\Rightarrow518-x=-36-12^2=-180\)

\(\Rightarrow x=-180-518=-698\)

\(b,2\left(x-5\right)=8\)

\(x-5=8\div2=4\)

\(x=4+5=9\)

                    Đặt \(A=\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}+\frac{1}{128}+\frac{1}{256}\)

                    \(A=\frac{1}{2^3}+\frac{1}{2^4}+\frac{1}{2^5}+\frac{1}{2^6}+\frac{1}{2^7}+\frac{1}{2^8}\)

                \(2A=\frac{1}{2^2}+\frac{1}{2^3}+\frac{1}{2^4}+\frac{1}{2^5}+\frac{1}{2^6}+\frac{1}{2^7}\)

               \(2A-A=\left(\frac{1}{2^2}+\frac{1}{2^3}+\frac{1}{2^4}+\frac{1}{2^5}+\frac{1}{2^6}+\frac{1}{2^7}\right)-\left(\frac{1}{2^3}+\frac{1}{2^4}+\frac{1}{2^5}+\frac{1}{2^6}+\frac{1}{2^7}+\frac{1}{2^8}\right)\)

              \(A=\frac{1}{2^2}-\frac{1}{2^8}\)

           \(A=\frac{1}{4}-\frac{1}{256}=\frac{63}{256}\)

          \(\Rightarrow\frac{63}{256}.x=\frac{1}{512}=\frac{1}{2^9}\)

           \(\Rightarrow\frac{63}{2^8}.x=\frac{1}{2^9}\)

            \(\Rightarrow x=\frac{1}{2^9}:\frac{63}{2^8}=\frac{1}{2^9}.\frac{2^8}{63}=\frac{1}{2.63}=\frac{1}{126}\)

           Ủng hộ mk nha !!! ^_^

64\(^x\) : 16\(^x\) = 256

(64: 16)^\(x\)  = 256

        4\(^x\)  = 4⁴

          \(x\) = 4

Vậy \(x\) = 4