`(a+5)xx[(140/a)-1]=150`

`<=>(a+5).((140-a)/a)=150`

`<=>(a+5)(140-a)=150a`

`<=>140a-a^2+700-5a=150`

`<=>700+135a-a^2=150`

`<=>a^2-15a-700=0`

`Delta=225+2800=3025`

`<=>a_1=35,a_2=-20`

Vậy `S={35,-20}`.

       \(\frac{150}{x-1}-\frac{140}{x}=5\)

\(ĐKXĐ:x\ne1;x\ne0\)

\(MTC:x\left(x-1\right)\) 

 \(\Leftrightarrow\frac{150x}{x\left(x-1\right)}-\frac{140\left(x-1\right)}{x\left(x-1\right)}=\frac{5x\left(x-1\right)}{x\left(x-1\right)}\)

\(\Rightarrow150x-140\left(x-1\right)=5x\left(x-1\right)\)

\(\Leftrightarrow150x-140x+140=5x^2-5x\)

\(\Leftrightarrow150x-140x+140-5x^2+5x=0\)

\(\Leftrightarrow-5x^2+15x+140=0\)

\(\Leftrightarrow-5x^2-20x+35x+140=0\)

\(\Leftrightarrow\left(-5x^2+35x\right)+\left(-20x+140\right)=0\)

\(\Leftrightarrow-5x\left(x-7\right)-20\left(x-7\right)=0\)

\(\Leftrightarrow\left(x-7\right)\left(-5x-20\right)=0\)

HOẶC \(x-7=0\Leftrightarrow x=7\)(nhận)

HOẶC\(-5x-20=0\Leftrightarrow x=-4\)(nhận)

VẬY TẬP NGHIỆM CỦA PT LÀ \(S=\left\{7;-4\right\}\)

\(\frac{150}{x-1}-\frac{140}{x}=5\)

\(\Leftrightarrow\frac{150x}{x\left(x-1\right)}-\frac{140\left(x-1\right)}{x\left(x-1\right)}=5\)

\(\Leftrightarrow\frac{150x-140\left(x-1\right)}{x\left(x-1\right)}=5\)

\(\Leftrightarrow\frac{150x-140x+140}{x\left(x-1\right)}=5\)

\(\Leftrightarrow\frac{10x+140}{x\left(x-1\right)}=5\)

\(\Leftrightarrow10x+140=5x\left(x-1\right)\)

\(\Leftrightarrow5\left(2x+28\right)=5x\left(x-1\right)\)

\(\Leftrightarrow2x+28=x\left(x-1\right)\)

\(\Leftrightarrow28=x\left(x-1\right)-2x\)

\(\Leftrightarrow28=x\left(x-1-2\right)\)

\(\Leftrightarrow28=x\left(x-3\right)\)

\(\Leftrightarrow x\left(x-3\right)=7.4=\left(-4\right)\left(-7\right)\)

\(\Leftrightarrow x\in\left\{7;-4\right\}\)

ĐKXĐ: \(x\ne0;1\)

Ta có: \(\frac{150}{x-1}-\frac{140}{x}=5\Leftrightarrow\frac{150x}{x\left(x-1\right)}-\frac{140\left(x-1\right)}{x\left(x-1\right)}=\frac{150x-140x+140}{x\left(x-1\right)}=5\)

\(\Leftrightarrow\frac{10x+140}{x\left(x-1\right)}=5\Leftrightarrow10x+140=5x\left(x-1\right)\Leftrightarrow10x+140=5x^2-5x\)

\(\Leftrightarrow5x^2-5x-10x-140=0\Leftrightarrow5x^2-15x-140=0\)

\(\Leftrightarrow x^2-3x-28=0\Leftrightarrow x^2-7x+4x-28=0\Leftrightarrow x\left(x-7\right)+4\left(x-7\right)=0\)

\(\Leftrightarrow\left(x+4\right)\left(x-7\right)=0\Leftrightarrow\orbr{\begin{cases}x+4=0\\x-7=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=-4\\x=7\end{cases}}}\)

Vậy...

\(\frac{150}{x-1}-\frac{140}{x}=5\left(ĐKXĐ:x\ne1,x\ne0\right)\\ \Leftrightarrow\frac{150x-140\left(x-1\right)}{x\left(x-1\right)}=\frac{5x\left(x-1\right)}{x\left(x-1\right)}\\ \Leftrightarrow150x-140x+140=5x^2-5x\\5x^2-5x-10x-140=0\\ \Leftrightarrow5x^2-15x-140=0\\ \Leftrightarrow5\left(x^2-3x-28\right)=0\\ \Leftrightarrow5\left[\left(x^2-3x+\frac{9}{4}\right)-28-\frac{9}{4}\right]=0\\ \Leftrightarrow5\left[\left(x-\frac{1}{2}\right)^2-\frac{121}{4}\right]=0\\ \Leftrightarrow5\left(x-\frac{1}{2}-\frac{11}{2}\right)\left(x-\frac{1}{2}+\frac{11}{2}\right)=0\\ \Leftrightarrow5\left(x-6\right)\left(x+5\right)=0\\ \Rightarrow\left[{}\begin{matrix}x-6=0\\x+5=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=6\\x=-5\end{matrix}\right.\\ Vậy...\)

x=-4 hoặc x=7

\(\frac{150}{x-1}-\frac{140}{x}=5\)

\(\Leftrightarrow\frac{150}{x-1}.x\left(x-1\right)-\frac{140}{x}.x\left(x-1\right)=5.x\left(x-1\right)\)

\(\Leftrightarrow150x-140\left(x-1\right)=5x\left(x-1\right)\)

\(\Leftrightarrow10x+140=5x^2-5x\)

\(\Leftrightarrow5x^2-5x=10x+140\)

\(\Leftrightarrow5x^2-5x-140=10x+140-140\)

\(\Leftrightarrow5x^2-5x-140=10x\)

\(\Leftrightarrow5x^2-5x-140=10x-10\)

\(\Leftrightarrow5x^2-5x-140=0\)

\(\Rightarrow\hept{\begin{cases}x=7\\x=-4\end{cases}}\)

Không chắc nha

\(ĐKXĐ:x\ne1\)

\(\frac{150}{x-1}-\frac{140}{x}=5\)

\(\Leftrightarrow\frac{150x}{x\left(x-1\right)}-\frac{140\left(x-1\right)}{x\left(x-1\right)}=5\)

\(\Leftrightarrow\frac{150x}{x\left(x-1\right)}-\frac{140x-140}{x\left(x-1\right)}=5\)

\(\Leftrightarrow\frac{150x-140x+140}{x\left(x-1\right)}=5\)

\(\Leftrightarrow150x-140x+140=5x\left(x-1\right)\)

\(\Leftrightarrow10x+140=5x\left(x-1\right)\)

\(\Leftrightarrow10\left(x+14\right)=5x\left(x-1\right)\)

\(\Leftrightarrow2\left(x+14\right)=x\left(x-1\right)\)

\(\Leftrightarrow2x+28=x^2-x\)

\(\Leftrightarrow3x+28=x^2\)

\(\Leftrightarrow3x-x^2=-28\)

\(\Leftrightarrow x\left(3-x\right)=-28\)

\(\Leftrightarrow x\left(3-x\right)=-4.7\)

\(\Leftrightarrow x=-4\)

\(\frac{150}{x-1}-\frac{140}{x-1}=5\left(ĐK:x\ne1\right)\)

\(\Leftrightarrow\frac{10}{x-1}=5\)

\(\Leftrightarrow x-1=2\)

\(\Leftrightarrow x=3\)

ĐKXĐ: x-1\(\ne\)0=> x\(\ne\)1

=> \(\frac{150-140}{x-1}\)=5

=> \(\frac{10}{x-1}\)=5

=> 10= 5(x-1)=> x-1=2=> x=1(ko thỏa mã ĐKXĐ x\(\ne\)1)

phương trình này vô nghiệm.

\(\frac{150}{x-1}-\frac{140}{x-1}\)= 5

\(\frac{150-140}{x-1}=5\)

\(\frac{10}{x-1}=5\)

\(\frac{10}{x-1}=\frac{5x-5}{x-1}\)

10 = 5x - 5 

-5x = -10 - 5

-5x = -15

x = -15 : -5

x = 3

\(\frac{150}{x-1}-\frac{140}{x}=5\)

\(a,3\left(x+1\right)-2=4\)

\(\Leftrightarrow3\left(x+1\right)=6\)

\(\Leftrightarrow x+1=2\)

\(\Leftrightarrow x=1\)

Vậy x=1

Các câu còn lại lm tương tự nhé

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

<=> \(3x+3-2=4\)

<=> \(3x=3\)

<=> \(x=1\)

\(5\left(x-2\right)+20=45\)

<=> \(5x-10=25\)

<=> \(x=7\)

\(700-7\left(x+2\right)=140\)

<=> \(7x+14=560\)

<=> \(7x=546\)

<=> \(x=78\)

\(200-5\left(2x+4\right)=100\)

<=> \(10x+20=100\)

<=> \(x=8\)

\(5\left(2x-4\right)+150=250\)

<=> \(10x-20=100\)

<=> \(x=12\)

học tốt

a) 3(x + 1) - 2 = 4                  b) 5(x-2) + 20 = 45              c )  700 - 7 ( x + 2 ) = 140          d) 200 - 5 ( 2x +4 ) = 100 

    3(x + 1 ) = 4 + 2                    5 ( x -2 ) = 45 - 20                 7 ( x + 2 ) = 700 - 140               5 ( 2x + 4 ) = 200 - 100 

    3( x  + 1 ) = 6                        5 ( x - 2 ) = 25                       7 ( x + 2 ) = 560                         5 ( 2x  +  4 )  = 100

    x + 1   = 6 : 3                         x  -  2    =  25 :  5                  x + 2  = 560 : 7                          ( 2x + 4 ) = 100 : 5

   x + 1 =  2                                x   -  2   =    5                       x  +  2 = 80                                 ( 2x + 4 )  =  20

  x        =  2 - 1                           x           =  5 + 2                   x          =  80 - 2                           2x    =  20 - 4

  x        =    1                              x            =   7                       x           =  78                               2x    =   16

Vậy x  = 1                             Vậy x  =   7                         Vậy x  =  78                                      => x = 8

                                                                                                                                          vậy x  =  8

Bày cho mik đi

(1225 + 625) - 4x = 1000 - 150

=> 1850 - 4x         = 950

=>            4x         = 1850 - 950

=>            4x         = 900

=>              x         = 900 : 4

=>              x         = 225

b) 43 - (24 - x) = 20

=>        24 - x   = 43 - 20

=>        24 - x   = 23

=>               x   = 24 - 23

=>               x   = 1

c) 245 - 5(16 + x) = 140

=>         5(16 + x) = 245 - 140

=>         5(16 + x) = 105

=>             16 + x  = 105 : 5

=>              16 + x = 21

=>                      x  = 21 - 16

=>                     x   = 5

\(a,\)\(\left(1225+625\right)-4x=1000-150.\)

\(\Rightarrow1850-4x=850\)\(\Rightarrow4x=1850-850=1000\)

\(b,43-\left(24-x\right)=20\)

\(\Rightarrow43-24+x=20\)\(\Rightarrow19+x=20\Leftrightarrow x=1\)

\(c,245-5\left(16+x\right)=140\)

\(\Rightarrow245-80-5x=140\)

\(\Rightarrow165-5x=140\Leftrightarrow5x=165-140=25\Leftrightarrow x=5\)