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23 tháng 6 2021

2x10+2x20+2x30+80:2+40:2+20

= 200

2x10+2x20+2x30+80:2+40:2+20=200

29 tháng 12 2021

x = \(\dfrac{4}{3}\)
x = -2
 

29 tháng 12 2021

(3x+1)\(^2\) = 5\(^2\)

3x+1     = 5

3x         = 5

x           = 5: 3

x           \(\approx\)1.6

 

7 tháng 10 2019

a) \(\left(x+\frac{1}{2}\right)^2=\frac{1}{16}\)

\(\Rightarrow x+\frac{1}{2}=\pm\frac{1}{4}\)

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

Vậy \(x\in\left\{-\frac{1}{4};-\frac{3}{4}\right\}.\)

b) \(\left(3x+1\right)^3=-27\)

\(\Rightarrow\left(3x+1\right)^3=\left(-3\right)^3\)

\(\Rightarrow3x+1=-3\)

\(\Rightarrow3x=\left(-3\right)-1\)

\(\Rightarrow3x=-4\)

\(\Rightarrow x=\left(-4\right):3\)

\(\Rightarrow x=-\frac{4}{3}\)

Vậy \(x=-\frac{4}{3}.\)

Mấy câu sau làm tương tự nhé.

Chúc bạn học tốt!

7 tháng 10 2019

c)\(\left(3x-2\right)^2=36\\ \Leftrightarrow\left(3x-2\right)^2=\left(\pm6\right)^2\\ \Rightarrow\left\{{}\begin{matrix}3x-2=6\\3x-2=-6\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=\frac{8}{3}\\x=-\frac{4}{3}\end{matrix}\right.\)

d)\(\left(\frac{2}{5}-3x\right)^2=\frac{9}{25}\\ \Leftrightarrow\left(\frac{2}{5}-3x\right)^2=\left(\pm\frac{3}{5}\right)^2\\ \Rightarrow\left\{{}\begin{matrix}\frac{2}{5}-3x=\frac{3}{5}\\\frac{2}{5}-3x=-\frac{3}{5}\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=-\frac{1}{15}\\x=\frac{1}{3}\end{matrix}\right.\)

4 tháng 11 2017

=>(2x+3).(10x+2)=(5x+2).(4x+5)

=>(2x.10x)+(2x.2)+(3.10x)+(3.2)=(5x.4x)+(5x.5)+(2.4x)+(2.5)

=>20x2+4x+30x+6=20x2+25x+8x+10

=>20x2-20x2+4x-8x+30x-25x=10-6

=>0+4x-8x+30x-25x=4

=>-4x+30x-25x=4

=>26x-25x=4

=>x=4

B)=>(3x-1).(5x-34)=(40-5x).(25-3x)

=>15x2-102x-5x+34=1000-120x-125x+15x2

=>15x2-107x+34=1000-245x+15x2

=>15x2-15x2-107x+245x=1000-34

=>0-107x+245x=966

=>138x=966

=>x=7

A,=>(2x+3).(10x+2)=(5x+2).(4x+5)

=>(2x.10x)+(2x.2)+(3.10x)+(3.2)=(5x.4x)+(5x.5)+(2.4x)+(2.5)

=>20x2+4x+30x+6=20x2+25x+8x+10

=>20x2-20x2+4x-8x+30x-25x=10-6

=>0+4x-8x+30x-25x=4

=>-4x+30x-25x=4

=>26x-25x=4

=>x=4

12 tháng 10 2021

b: \(\left(17x-25\right):8+65=9^5:9^3\)

\(\Leftrightarrow\left(17x-25\right):8=9^2-65=81-65=16\)

\(\Leftrightarrow17x-25=128\)

hay x=9

 

12 tháng 10 2021

b: (17x−25):8+65=95:93(17x−25):8+65=95:93

⇔(17x−25):8=92−65=81−65=16⇔(17x−25):8=92−65=81−65=16

⇔17x−25=128⇔17x−25=128

hay x=9

 

30 tháng 12 2021

a  x = \(\dfrac{-1}{12}\)

b  x = \(\dfrac{-4}{3}\)

c  x = \(\dfrac{-1}{6}\)

d  x = \(\dfrac{-1}{4}\)

30 tháng 12 2021

\(\left(4x+1\right)^2=\dfrac{4}{9}\)

\(\left(4x+1\right)=\perp\left(\dfrac{2}{3}\right)^2\)

\(\text{Vậy }4x+1=\dfrac{2}{3}\)

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

        \(x\)         \(=\left(\dfrac{-1}{3}\right).\dfrac{1}{4}=\dfrac{-1}{12}\)

\(\text{hoặc }4x+1=\dfrac{-2}{3}\)

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

         \(x\)         \(=\left(\dfrac{-5}{3}\right).\dfrac{1}{4}=\dfrac{-5}{12}\)

\(\Rightarrow x\in\left\{\dfrac{-1}{12};\dfrac{-5}{12}\right\}\)

\(\left(3x-1\right)^2=25\)

\(\left(3x-1\right)^2=\perp\left(5\right)^2\)

\(\text{Vậy }3x-1=5\)

       \(3x\)        \(=5+1=6\)

        \(x\)         \(=6:3=2\)

\(\text{hoặc }3x-1=-5\)

        \(3x\)       \(=\left(-5\right)+1=-4\)

         \(x\)        \(=\left(-4\right):3=\dfrac{-4}{3}\)

\(\Rightarrow x\in\left\{2;\dfrac{-4}{3}\right\}\)

\(\left(x-\dfrac{1}{3}\right)^2=\dfrac{1}{4}\)

\(\left(x-\dfrac{1}{3}\right)^2=\perp\left(\dfrac{1}{2}\right)^2\)

\(\text{Vậy }x-\dfrac{1}{3}=\dfrac{1}{2}\)

       \(x\)         \(=\dfrac{1}{2}+\dfrac{1}{3}=\dfrac{5}{6}\)

\(\text{hoặc }x-\dfrac{1}{3}=\dfrac{-1}{2}\)

        \(x\)         \(=\left(\dfrac{-1}{2}\right)+\dfrac{1}{3}=\dfrac{-1}{6}\)

\(\Rightarrow x\in\left\{\dfrac{5}{6};\dfrac{-1}{6}\right\}\)

\(\left(4x-3\right)^2=16\)

\(\left(4x-3\right)=\perp\left(4\right)^2\)

\(\text{Vậy }4x-3=4\) 

        \(4x\)       \(=4+3=7\)

          \(x\)       \(=7:4=\dfrac{7}{4}\)

\(\text{hoặc }4x-3=-4\)

        \(4x\)        \(=\left(-4\right)+3=-1\)

          \(x\)        \(=\left(-1\right):4=\dfrac{-1}{4}\)

\(\Rightarrow x\in\left\{\dfrac{7}{4};\dfrac{-1}{4}\right\}\)

24 tháng 8 2018

\(\left(\frac{2}{5}-3x\right)^2=\frac{9}{25}\)

\(\Rightarrow\left(\frac{2}{5}-3x\right)^2=\left(\frac{3}{5}\right)^2\)

\(\Rightarrow\frac{2}{5}-3x=\frac{3}{5}\)

\(\Rightarrow3x=\frac{-1}{5}\)

\(\Rightarrow x=\frac{-1}{15}\)

24 tháng 8 2018

(2/5 - 3 x ) ^2 = ( 3 / 5 )^ 2 

-> 2/5 - 3x = 3/5 

              3x= 2/5 - 3/5

                3x=-1/5

                  x= -1/5 : 3 

                   x=-1/15