a,

(x + 82,7 ) x 0,01 = 2,056

x + 82,7 = 2,056 : 0,01

x + 82,7 = 205,6

x = 205,6 - 82,7

x = 122,9

b,

x : 3 / 5 = 7 / 9 - 1 / 3

x : 3 / 5 = 4 / 9

x = 4 / 9 x 3 / 5

x = 4 / 15

( x + 82,7 ) x 0,01 = 2,056

( x + 82,7 )            = 2,056  : 0,01

( x + 82,7 )            = 205,6

  x                         = 205,6 - 82,7

  x                         = 122,9

x : \(\frac{3}{5}\)= \(\frac{7}{9}\)-\(\frac{1}{3}\)

x : \(\frac{3}{5}\)= \(\frac{4}{9}\)

x            = \(\frac{4}{9}\)x \(\frac{3}{5}\)

x            = \(\frac{4}{15}\)

ko bi

k too

Ai giúp mình với ạ !

x=2.056:0.01-82.7

x=205.6-82.7

x=122.9

\(\frac{x}{4}=9x\)

\(\Leftrightarrow36x=x\)

\(\Leftrightarrow36x-x=0\)

\(\Leftrightarrow35x=0\)

\(\Leftrightarrow x=0\)

mình nhầm 9/x nha

\(\frac{x}{4}=\frac{9}{x}\)

\(\Leftrightarrow x^2=36\)

\(\Leftrightarrow\orbr{\begin{cases}x=6\\x=-6\end{cases}}\)

Vậy x=6; x=-6

(x+1) + (x+2) + (x+3) + (x+4) + ...+ (x+30) = 795

x.30 + (1+30).30 : 2 = 795

30x + 465 = 795

30x = 330

x = 11

( x + 1 ) + ( x + 2 ) + ( x + 3 ) + ( x + 4 ) + .... + ( x + 30 ) = 795

 ( x + x + x + x + ...+ x ) + ( 1 + 2  + 3 + 4 + ... +  30 ) = 795

 Tổng số các số hạng là : ( 1 + 30 ) . 30 : 2 = 465

=> x. 30 + 465 = 795

=> x . 30 = 330

=> x = 11

Vậy x = 11

cau re ot the cung dang nen

1.   x-6:2-(48-24):2:6-3=0

      x-6:2-(48-24):2:6=3

      x-6:2-24:2:6=3

      x-6:2-12:6= 3

      x-3-2=3

      x-3=5

       x= 8

Vậy x=8

(20,07+2008x20,09) x (2011x0,01-20,01)

= (20,07+2008x20,09) x (20,01-20,01)

= (20,07+2008x20,09) x 0

=0

Kết quả = 0 nhé

(20,07 + 2008 x 20,09) x (2011 x 0,01 - 20,11)

= (20,07 + 2008 x 20,09) x 0

= 0

Bn có nhầm đề ko chỗ 20,01 là 20, 11 nhé

x=0;2;4;14 nha bn kick mik nha 

thanks

\(\left(\frac{1}{1\cdot2\cdot3}+\frac{1}{2\cdot3\cdot4}+\frac{1}{3\cdot4\cdot5}+...+\frac{1}{8\cdot9\cdot10}\right)x=\frac{22}{45}\)

\(\Rightarrow\frac{1}{2}\left(\frac{2}{1\cdot2\cdot3}+\frac{2}{2\cdot3\cdot4}+\frac{2}{3\cdot4\cdot5}+...+\frac{2}{8\cdot9\cdot10}\right)x=\frac{22}{45}\)

\(\Rightarrow\frac{x}{2}\left(\frac{1}{1\cdot2}-\frac{1}{2\cdot3}+\frac{1}{2\cdot3}-\frac{1}{3\cdot4}+...+\frac{1}{8\cdot9}-\frac{1}{9\cdot10}\right)=\frac{22}{45}\)

\(\Rightarrow\frac{x}{2}\left(\frac{1}{2}-\frac{1}{90}\right)=\frac{22}{45}\)

\(\Rightarrow\frac{x}{2}\cdot\frac{22}{45}=\frac{22}{45}\)

\(\Rightarrow\frac{x}{2}=1\)

\(\Rightarrow x=2\)

\(\left|3x+5\right|=11-2x\)   \(\text{Đ}K:11-2x\ge0\)

<=>\(3x+5=\pm11-2x\)

TH1: \(3x+5=11-2x\)                                                              TH2 : \(3x+5=-\left(11-2x\right)\)

    <=>\(3x+2x=11-5\)                                                                  <=>\(3x+5=-11+2x\)

   <=>\(5x=6\)                                                                                           <=>\(3x-2x=-11-5\)

    <=> \(x=\frac{6}{5}\)                                                                                          <=> \(x=-16\)

                                     \(V\text{ậy}\orbr{\begin{cases}x=\frac{6}{5}\\x=-16\end{cases}}\)

\(\left|3x+5\right|=11-2x\)

Từ biểu thức trên ta có thể suy ra \(\left|3x+5\right|=\pm11-2x\)( 11 - 2x > 0 )

+TH1:

\(\left|3x+5\right|=11-2x\)

\(\Rightarrow3x+2x=11-5\)

\(\Rightarrow5x=6\)

\(\Rightarrow x=\frac{6}{5}\)

+TH2:

\(\left|3x+5\right|=\left(-11\right)-2x\)

\(\Rightarrow3x-2x=\left(-11\right)-5\)

\(\Rightarrow x=-16\)

Vậy x \(\in\left\{\frac{6}{5};-16\right\}\)

l 3x + 5 l = 11 - 2x

=> hoặc 3x + 5 = 11 - 2x

3x + 5 + 2x = 11

5x + 5 = 11

5 . ( x + 1 ) = 11

x + 1 = \(\frac{11}{5}\)

x = \(\frac{6}{5}\)

hoặc  3x + 5  = - ( 11 - 2x )

3x + 5 = ( - 11 ) + 2x

3x + 5 - 2x = - 11

x + 5 = - 11

x = - 11 - 5

x = - 16

Vậy x thuộc { 6/5 ; - 16 }