a) 315 + 2x = x+115

<=> 2x-x = 115-315

<=> x = -200

Vậy x= -200

b) 25-(30-x)=25-(-12+125)

<=> 25-30+x = -88

<=> -5 + x =-88

<=> x = -83

Vậy x=-83

c) 412-(40-2x) = 72+x

<=> 412-40+2x=72+x

<=> 372 + 2x = 72+x

<=> 2x-x = 72-372

<=> x= -300

Vậy x=-300

=> 315+2x-125-x=412

      315+2x-125-x=412

    315+2x+(-125)+(-x)=412

 315+(-125)+2x+(-x)=412

   190+2x+(-x)=412

          x=412-190

           x=222

    đúng 100% 

tick đúng nghe

kết bn vs mjk nha

a ) 4 1 2 − x = − 3 2 3 ⇒ x = 4 1 2 + 3 2 3 = 9 2 + 11 3 = 8 1 6 .

b ) x − 2 2 3 = 3 1 3 ⇒ x = 2 2 3 + 3 1 3 = 6

a) x = 1         

b) x = -3

\(a)15.\left(\dfrac{212121}{434343}+\dfrac{333333}{353535}\right)\)

\(=15.\left(\dfrac{21}{43}+\dfrac{33}{35}\right)\)

\(=15.\dfrac{2154}{1505}\)

\(=\dfrac{6462}{301}\)

x = 344 + 125

x = 469

b) x + 125 = 266

x = 266 - 125

x = 141

1 a/ B = 2016 . 2016 - 2014 . 2018

           =\(2016^2-\left(2016-2\right).\left(2016+2\right)\)

           = \(2016^2-2016.\left(-2+2\right)\\\)

           =\(2016^2-2016.0 \)

           = \(2016^2\)

1: Tính
a) B = 2016 x 2016 - 2014 x 2018
       = (2016 x 2016) - (2014 x 2018)
       =  4064256 - 4064252
       = 4
       b) 327 x 412 + 400 / 328 x 412 -12
          = (327 x 412 + 400) / ( 328 x 412 - 12)
           = 135124 / 135124
           = 1

c) ( 1234 x 567 - 667 ) : ( 567 + 1234 x 5)
   = (1234 x 567 - 667) : (567 + 1234 x 566) 
= [1234 x 566 + (1234 - 667)] / (1234 x 566 + 567) 
= (1234 x 566 + 567) / (1234 x 566 + 567)
= 1
để thiếu bạn ơi
 

125-30-x-125=x-237-8+237

-30-x=x-8

=> -30=2x-8

=> x=-11