\(\left(x+15\right)\left(x+6\right)=136\)

\(\Leftrightarrow x^2+21x-46=0\)

\(\Leftrightarrow\left(x+23\right)\left(x-2\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=-23\\x=2\end{matrix}\right.\)

\(\left(15+x\right)\left(6+x\right)=136\)

\(\Leftrightarrow x^2+21x-46=0\)

\(\Leftrightarrow\left(x-2\right)\left(x+23\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x-2=0\\x+23=0\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}x=2\\x=-23\end{matrix}\right.\)

(15 + x)(6 + x) = 136

<=> 90 + 15x + 6x + x² = 136

<=> 90 + 21x + x² = 136

<=> x² + 21x - 46 = 0

<=> x² + 2x - 23x - 46 = 0

<=> x(x + 2) - 23(x + 2) = 0

<=> (x - 23)(x + 2) = 0

<=> \(\left[{}\begin{matrix}x-23=0\\x+2=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=23\\x=-2\end{matrix}\right.\)

`a)1/2+[-1]/[-3]-5/12 < 2x < 12/[-31]+136/31`

`186/372+124/372-155/372 < [744x]/372 < [-144]/372+1632/372`

`186+124-155 < 744x < -144+1632`

`155 < 744x < 1488`

`155:744 < 744x:744 < 1488:744`

`5/24 < x < 2`

Vậy `5/24 < x < 2`

__________________________________________________

`b)[-2]/5 < x/15 < 1/6`

`[-12]/30 < [2x]/30 < 5/30`

`-12 < 2x < 5`

`-12:2 < 2x:2 < 5:2`

`-6 < x < 5/2`

Vậy `-6 < x < 5/2`

Giải:

a) x - \(\dfrac{9}{25}\)= \(\dfrac{16}{25}\)

x = \(\dfrac{16}{25}\)+\(\dfrac{9}{25}\)
x = \(\dfrac{25}{25}\)

x = 1

b) \(\dfrac{-12}{30}\)<\(\dfrac{x}{30}\)<\(\dfrac{5}{30}\)

=> x có thể bằng \(\dfrac{-11}{30}\) đến \(\dfrac{4}{30}\)
=> x bằng -5; -4; -3; -2; -1;0;1;2

Mình cần gấp

29150-136x201

29150-27336

1814

8/15 : 2/11 + 7/15 : 2/11 = (8/15+7/15):2/11=

15/15x11/2=11/2

a/ (ghi lại cái đề)

=>+ 3x-7=2                                                                 

3x=2+7=9

x=3

     + 3x-7=-2

 3x=-2+7=5

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

b/ (5x-10)²=100

=> +5x-10=10

5x=10+10=20

x=4

      + 5x-10=-10

5x=-10+10=0

x=0

a/ x=3 và 5/3

b/ (5x-10)²=100

=> +5x-10=10

5x=10+10=20

x=4

      + 5x-10=-10

5x=-10+10=0

x=0

c/(-4x+5)³=-27

-4x+5=-3

-4x=-8

x=2

pt <=> \(x^2+21x+90=136\)

<=> \(x^2+21x-46=0\)

<=> \(x^2-2x+23x-46=0\)

<=> \(\left(x-2\right)\left(x+23\right)=0\)

<=> \(\orbr{\begin{cases}x=2\\x=-23\end{cases}}\)

Vậy tập hợp nghiệm của pt là S={2;-23}.

\(\left(15+x\right)\left(6+x\right)=136\)

\(\Leftrightarrow90+15x+6x+x^2=136\)

\(\Leftrightarrow-46+21x+x^2=0\)

\(\Leftrightarrow\left(x-2\right)\left(x+23\right)=0\Leftrightarrow\orbr{\begin{cases}x=2\\x=-23\end{cases}}\)

( 15 + x )( 6 + x ) = 136

<=> 90 + 21x + x² = 136

<=> x² + 21x + 90 - 136 = 0

<=> x² + 21x - 46 = 0

<=> x² - 2x + 23x - 46 = 0

<=> x( x - 2 ) + 23( x - 2 ) = 0

<=> ( x + 23 )( x - 2 ) = 0

<=> \(\orbr{\begin{cases}x+23=0\\x-2=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=-23\\x=2\end{cases}}\)

a, 75 - 5 . ( 15 - 10 ) - ( -60 ) = 75 - 5 . 5 + 60 = 135 - 25 = 110

b, 136 - ( -7 ) + 6 - 23 - 36 = 136 + 7 + 6 - 23 - 36 = ( 136 - 36 ) + ( 7 + 6 - 23 ) = 100 - 10 = 90

c, ( -15 - 17 ) . ( -15 + 7 ) = -32 . ( -8 ) = 256

d, ( -9 - 18 ) : ( -9 ) = -27 : ( -9 ) = 3

Bài 2:

a, 2x - 17 = ( -3x - 18 )

<=> 2x + 3x = 17 - 18

<=> 5x = -1

<=> x = -1/5

b, ( 13 - IxI ) + 15 = 20

<=> 13 - |x| = 5

<=> |x| = 8

<=> x = 8 hoặc x = -8  

c, Ix + 5I - ( x + 5 ) = 0

<=> |x + 5| = x + 5 

Đk: x + 5 ≥ 0 => x ≥ -5

\(\Leftrightarrow\orbr{\begin{cases}x+5=x+5\\x+5=-x-5\end{cases}\Leftrightarrow}\orbr{\begin{cases}0x=0\\2x=-10\end{cases}\Leftrightarrow}\orbr{\begin{cases}x\ge-5\\x=-5\end{cases}}\)

Vậy  x ≥ -5

\(130+\frac{x}{3}=136\Leftrightarrow\frac{x}{3}=6\Leftrightarrow x=18\)

\(\frac{\left(x-15\right)}{2}=25\Leftrightarrow x-15=50\Leftrightarrow x=65\)

130+x:3=136

x:3=136-130

x:3=6

x=6.3

x=18

(x-15):2=25

x-15=25.2

x-15=50

x=50+15

x=65

k cho 

mình đi

130 + x : 3= 136                               (x-15) : 2=136

x:3           = 136-130                         X-15      = 136*2

x:3           = 6                                    X-15      =  272

x              = 6*3                                x             = 272+15

x              = 18                                 x             = 287