(4x – 5 ) chia het (2x – 1 ) 7 chia het ( x – 1)

1 bình luận về “(4x – 5 ) chia het (2x – 1 ) 7 chia het ( x – 1)”

1. #Chanhh

   ( 4x – 5 ) \vdots ( 2x – 1 )

   => 4x – 5 = 4x – 2 – 3

                   = 2(2x – 1 ) – 3

   @ Vì 2(2x – 1 )  \vdots (2x – 1 )

   Để (4x – 5 ) \vdots (2x – 1 )

   Thì 3 \vdots ( 2x – 1 )

   => ( 2x – 1 ) in U(3)

   U(3) = { 1 ; 3 }

   Vậy ( 2x – 1 ) in { 1 ; 3}

   @ 2x – 1= 1                             

   => 2x = 1 + 1

   => 2x = 2

   => x = 2/2

   => x = 1

   @ 2x – 1 = 3

   => 2x = 3 + 1

   => 2x = 4

   => x = 4/2

   => x = 2

   Vậy x in NN nên x in { 1 ; 2}

   __

   7 \vdots ( x – 1)

   @ Vì 7 \vdots ( x – 1)

   Nên ( x – 1) in U(7)

   U(7) = { 1 ;7}

   Vậy (x – 1 ) in { 1 ; 7 }

   @ x – 1 = 1

   => x = 1 + 1

   => x =2

   @x – 1 = 7

   => x = 7 + 1

   => x = 8

   Vậy x in NN nên x in { 2 ; 8 }

   Trả lời