Question

Tìm x :

5 ( x - 1 ) - 6 ( x + 1 ) = 7

 

Answer 1

     5 ( x - 1 ) - 6 ( x + 1 ) = 7

=>   5x - 5 - 6x - 6          = 7  

=>   5x - 6x - ( 5 + 6 )     = 7

=>   -x - 11                    = 7

=>   -x                           = 7 + 11

=>.   -x                           = 18

=>     x                          = -18

Answer 2

5( x - 1 ) - 6( x + 1 ) = 7

<=> 5x - 5 - 6x - 6 = 7

<=> ( 5x - 6x ) + ( -5 + -6) = 7

<=> -x - 11 = 7

<=> -x = 7 + 11

<=> -x = 18

<=> x = -18

Vậy x=-18

Answer 3

5 ( x - 1 ) - 6 ( x + 1 ) 

 5x - 5 - 6x - 6  = 7

( - 1 )x - 11 = 7

( - 1 ) x = 7 + 11 = 18

x = 18 : ( - 1 )

x = -18

Answer 4

5(x-1)-6(x+1)=7

5(x-1)-6(x-1+2)=7

5(x-1)-[6(x-1)+12]=7

5(x-1)-6(x-1)-12=7

(x-1).(-1)=19

x-1=-19

x=-18