29 - ( 209/10 * x - 80 ) : 2010/29 = 0

( 209/10 * x - 80 ) : 2010/29 = 29 - 0

( 209/10 * x - 80 ) : 2010/29 = 29

( 20,9 * x -80 ) = 29 * 2010/ 29

( 20,9 * x -80 ) = 2010

20,9 * x = 2010 + 80

20,9 * x = 2090

x = 2090 : 20,9

x = 100

HOK TỐT

29 - (\(\frac{209}{10}\)*X - 80 ) : \(\frac{2010}{29}\)=0

giải

(\(\frac{209}{10}\)* X - 80 ) : \(\frac{2010}{29}\)= 29

\(\frac{209}{10}\)* X - 80 )=29 x \(\frac{2010}{29}\)

\(\frac{209}{10}\)* X - 80 = 2010

\(\frac{209}{10}\)* X = 2010 + 80

\(\frac{209}{10}\)* X= 2090

X= 2090 : \(\frac{209}{10}\)

X= 2090 * \(\frac{10}{209}\)

X=100

29 -(209/10*x - 80)* 29/2010=0

29 - (6061/20100*x - 232/201) = 0

29 - 6061/20100*x + 232/201=0

6061/201 - 6061/20100*x = 0

606100 - 6061*x = 0

-6061*x = -606100

x = 100

\(29-\left(\frac{209}{10}x-80\right)=0\)

\(\Leftrightarrow\frac{209}{10}x-80=29\)

\(\Leftrightarrow\frac{209}{10}x=109\Leftrightarrow x=\frac{1090}{209}\)

Chịu???

a) -(x-6)=18

-x+6=18

-x=12

a) -18-(x-6)=0

          x-6=(-18)-0

          x-6=-18

          x   = (-18)+6

          x   = -12

b) 29-(10+29)=x-(27-9)

   29-39        = x-18

     -10         =x-18

     x-18=-10

     x    = (-10)+18

     x    = 8

Học tốt

Trl:

a) \(-18-\left(x-6\right)=0\)

\(\Rightarrow\left(x-6\right)=-18-0\)

\(\Rightarrow\left(x-6\right)=-18\)

\(\Rightarrow x=-18+6\)

\(\Rightarrow x=-12\)

b) \(29-\left(10+29\right)=x-\left(27-9\right)\)

\(\Rightarrow29-39=x-18\)

\(\Rightarrow-10=x-18\)

\(\Rightarrow x=18+\left(-10\right)\)

\(\Rightarrow x=28\)

1,7-(18+x)=-15

<=>18+x=7+15

<=>18+x=22

<=>x=4

2,(x-17)-(-3)=0

<=>x-17+3=0

<=>x-17=-3

,<=>x=14

<=>

1, 

7 - ( 18 + x ) = - 15 

18 + x = 7 + 15 

18 + x = 22

x = 22 - 18 

x = 4 

2,

( x - 17 ) - ( - 3 ) = 0 

( x - 17 ) + 3 = 0 

x - 17 = - 3 

x = -3 + 17 

x = 14 

3, -18 - ( x - 6 ) = 0 

-18 = x- 6 

x = - 18 + 6 

x = - 12 

4,   29 - ( 10 + 29 ) = x - ( 27 - 9 )

-10 = x - 18 

x = - 10 + 18 

x = 8

a, bổ sung đề 

 \(\dfrac{29-x}{21}+1+\dfrac{27-x}{23}+1+\dfrac{25-x}{25}+1+\dfrac{23-x}{27}+1+\dfrac{21-x}{29}+1=0\)

\(\Leftrightarrow\dfrac{50-x}{21}+\dfrac{50-x}{23}+\dfrac{50-x}{25}+\dfrac{50-x}{27}+\dfrac{50-x}{29}=0\)

\(\Leftrightarrow\left(50-x\right)\left(\dfrac{1}{21}+\dfrac{1}{23}+\dfrac{1}{25}+\dfrac{1}{27}+\dfrac{1}{29}\ne0\right)=0\Leftrightarrow x=50\)

C.29

`@` `\text {Ans}`

`\downarrow`

`a)`

\(2^{n+3}\cdot5^{n+3}=20^9\div2^9\)

`=>`\(\left(2\cdot5\right)^{n+3}=\left(20\div2\right)^9\)

`=>`\(10^{n+3}=10^9\)

`=>`\(n+3=9\)

`=> n = 9 - 3`

`=> n= 6`

Vậy, `n=6`

`b)`

\(3^{n+5}-3^{n+4}=1458\)

`=> 3^n*3^5 - 3^n*3^4 = 1458`

`=> 3^n*(3^5 - 3^4) = 1458`

`=> 3^n*162 = 1458`

`=> 3^n = 1458 \div 162`

`=> 3^n = 9`

`=> 3^n = 3^2`

`=> n=2`

Vậy, `n=2.`

`c)`

\(5^{n+3}+5^{n+2}=3750\)

`=> 5^n*5^3 + 5^n*5^2 = 3750`

`=> 5^n*(5^3+5^2) = 3750`

`=> 5^n*150 = 3750`

`=> 5^n = 3750 \div 150`

`=> 5^n =25`

`=> 5^n = 5^2`

`=> n=2`

Vậy, `n=2.`

`d)`

\(\dfrac{2}{7}x+\dfrac{3}{14}x=\dfrac{1}{2}\)

`=> 1/2x = 1/2`

`=> x = 1/2 \div 1/2`

`=> x=1`

Vậy, `x=1`

`e)`

\(\dfrac{x+2}{-3}=\dfrac{-2}{x+3}\)

`=> (x+2)(x+3) = -3*(-2)`

`=> (x+2)(x+3) = -6`

`=> x(x+3) + 2(x+3) = -6`

`=> x^2 + 3x + 2x + 6 = -6`

`=> x^2 + 5x + 6 - 6 = 0`

`=> x^2 + 5x = 0`

`=> x(x+5) = 0`

`=>`\(\left[{}\begin{matrix}x=0\\x+5=0\end{matrix}\right.\)

`=>`\(\left[{}\begin{matrix}x=0\\x=-5\end{matrix}\right.\)

Vậy, `x \in {0; -5}`

`@` `\text {Kaizuu lv u}`

1) \(A=\frac{7}{10\times11}+\frac{7}{11\times12}+\frac{7}{12\times13}+...+\frac{7}{69\times70}\)

    \(A=7\times\left(\frac{1}{10\times11}+\frac{1}{11\times12}+\frac{1}{12\times13}+...+\frac{1}{69\times70}\right)\)

    \(A=7\times\left(\frac{1}{10}-\frac{1}{11}+\frac{1}{11}-\frac{1}{12}+\frac{1}{12}-\frac{1}{13}+...+\frac{1}{69}-\frac{1}{70}\right)\)

    \(A=7\times\left(\frac{1}{10}-\frac{1}{70}\right)\)

   \(A=7\times\frac{3}{35}\)

   \(A=\frac{3}{5}\)

2) \(B=\frac{1}{25\times27}+\frac{1}{27\times29}+\frac{1}{29\times31}+...+\frac{1}{73\times75}\)

    \(B=\frac{1}{2}\times\left(\frac{2}{25\times27}+\frac{2}{27\times29}+\frac{2}{29\times31}+...+\frac{2}{73\times75}\right)\).

    \(B=\frac{1}{2}\times\left(\frac{1}{25}-\frac{1}{27}+\frac{1}{27}-\frac{1}{29}+\frac{1}{29}-\frac{1}{31}+...+\frac{1}{73}-\frac{1}{75}\right)\)

    \(B=\frac{1}{2}\times\left(\frac{1}{25}-\frac{1}{75}\right)\)

    \(B=\frac{1}{2}\times\frac{2}{75}\)

    \(B=\frac{1}{75}\)

3) \(C=\frac{4}{2\times4}+\frac{4}{4\times6}+\frac{4}{6\times8}+...+\frac{4}{2008\times2010}\)

    \(C=\frac{4}{2}\times\left(\frac{2}{2\times4}+\frac{2}{4\times6}+\frac{2}{6\times8}+...+\frac{2}{2008\times2010}\right)\)

    \(C=2\times\left(\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+\frac{1}{6}-\frac{1}{8}+...+\frac{1}{2008}-\frac{1}{2010}\right)\)

    \(C=2\times\left(\frac{1}{2}-\frac{1}{2010}\right)\)

    \(C=2\times\frac{502}{1005}\)

    \(C=\frac{1004}{1005}\)

_Chúc bạn học tốt_

a,\(7-\left(18+x\right)=-15\)

\(18+x=7-\left(-15\right)\)

\(18+x=22\)

\(x=4\)

b,\(\left(x-17\right)-\left(-3\right)=0\)

\(x-17=-3\)

\(x=14\)

c,\(-18-\left(x-6\right)=0\)

\(x-6=-18\)

\(x=-12\)

d,\(29-\left(10+29\right)=x-\left(27-9\right)\)

\(x-18=-10\)

\(x=8\)

a) \(7-\left(18+x\right)=-15\)

\(\Leftrightarrow18+x=7+15\)

\(\Leftrightarrow18+x=22\)

\(\Leftrightarrow x=22-18\)

\(\Leftrightarrow x=4\)

b) \(\left(x-17\right)-\left(-3\right)=0\)

\(\Leftrightarrow\left(x-17\right)+3=0\)

\(\Leftrightarrow x-17=0-3\)

\(\Leftrightarrow x-17=-3\)

\(\Leftrightarrow x=-3+17\)

\(\Leftrightarrow x=14\)

c) \(-18-\left(x-6\right)=0\)

\(\Leftrightarrow x-6=0+\left(-18\right)\)

\(\Leftrightarrow x-6=-18\)

\(\Leftrightarrow x=-18+6\)

\(\Leftrightarrow x=-12\)

d) \(29-\left(10+29\right)=x-\left(27-9\right)\)

\(\Leftrightarrow29-10-29=x-27+9\)

\(\Leftrightarrow-10=x-27+9\)

\(\Leftrightarrow x-27=-10-9\)

\(\Leftrightarrow x-27=-19\)

\(\Leftrightarrow x=-19+27\)

\(\Leftrightarrow x=8\)

a)
7 - (18 + x) = -15
18 + x = 7 - ( -15 )
18 + x = 7 + 15
18 + x = 22
x = 22 - 18
x = 4
b)
(x - 17) - (-3) = 0
x - 17 = 0 + -3
x - 17 = -3
x = -3 + 17
x = 14
c)
-18 - (x - 6) = 0
x - 6 = -18 - 0
x - 6 = -18
x = -18 + 6
x = -12
d)
29 - (10 + 29) = x - (27 - 9)
29 - 39 = x - 18
x - 18 = -10
x = -10 + 18
x = 8