X x 1999 - x = 1999 x 1997 + 1999

X x (1999 - 1) = 1999 x (1997 + 1)

X x 1998 = 1999 x 1998

Vậy x = 1999

2x1999-5=1999x1999+1999

x=1999

nha

x=1999

a) 210 : x = 14,92 - 6,52

    210 : x = 8,4

             x = 210 : 8,4

             x = 25

Vậy x = 25

a, 210 : x = 8,4

             x = 210 : 8,4

             x = 25

b, 5 x X - 1952 = 2500 - 1947

5 x X - 1952 = 553

5 x X = 553 + 1952

5 x X = 2505

      X = 2505 : 5

      X = 501

c, X x 1999 - x = 1999 x 1997b + 1999

X x 1998 = 1999 x 1997b + 1999

Mình hơi bí câu này, thông cảm

a, 210 : x = 14,92 - 6,52

210 : x = 8,4

x = 210 : 8,4

x = 25

b, 5 x x - 1952 = 2500 - 1947

5 x x - 1952 = 553 

5 x x = 553 + 1952

5 x x = 2505

x = 2505 : 5 

x = 501

bn coi lại câu cuối nhé mk nghĩ là nó thừa b ở 1997

theo mk là 

x x 1999 - x = 1999 x 1997 + 1999

x x ( 1999 - 1 ) = 1999 x ( 1997 + 1) 

x x 1998 = 1999 x 1998 

vậy x = 1999

a , x = 501

b , x = 1999

a) 5 * x - 1952 = 2500 - 1947

    5 * x -1952 =553

    5 * x             = 553 + 1952

    5 * x             =2505

    x                   = 501

b)x * 1999 - x = 1999*1997 +1999

 x * ( 1999 -1) = 1999*(1997 +1)

 x * 1998          =1999 * 1998

x                        =1999

`a)6x(x-1999)-x+1999=0`

`<=>6x(x-1999)-(x-1999)=0`

`<=>(x-1999)(6x-1)=0`

`<=>` \(\left[ \begin{array}{l}x-1999=0\\6x-1=0\end{array} \right.\) 

`<=>` \(\left[ \begin{array}{l}x=1999\\x=\dfrac16\end{array} \right.\) 

`b)x^2-9-4(x+3)=0`

`<=>(x-3)(x+3)-4(x+3)=0`

`<=>(x+3)(x-3-4)=0`

`<=>(x+3)(x-7)=0`

`<=>` \(\left[ \begin{array}{l}x+3=0\\x-7=0\end{array} \right.\) 

`<=>` \(\left[ \begin{array}{l}x=7\\x=-3\end{array} \right.\) 

\(\Leftrightarrow\left(x+3\right)\left(x-7\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=-3\\x=7\end{matrix}\right.\)

Vậy ...

X * 1999 - x = 1999 x 1997 + 1999

X * 1998      = 1999 x 1998

=> x = 1999

1999x-(-x)=1999.1997+1999

<=>2000x=3994002

<=>x=1997,001

\(a.\left(x\times0,25+1999\right)\times2000=2052\times2000\\ \left(x\times0,25+1999\right)\times2000=4104000\\ x\times0,25+1999=4104000:2000\\ x\times0,25+1999=2052\\ x\times0,25=2052-1999\\ x\times0,25=53\\ x=53:0,25\\ x=212\)

X.1999.X=1999.1997+1999

X.1999.X=1999.1997+1999.1

X.X.1999=1999.(1997+1)

X.X.1999=1999.1998

X.X=1999.1998:1999=1998

 X × 1999 × X = 1999 × 1997 + 1999

X^2 x 1999 = 1999 × 1997 + 1999 x 1

X^2 x 1999 = 1999 x ( 1997 + 1 )

X^2 x 1999 = 1999 x 1998

X^2 = 1999 x 1998 : 1999

X^2 = 1999 : 1999 x 1998

X^2 = 1 x 1998

X^2 = 1998