$( 2x + 1)^{2}$ – 4 $(x – 1)^{2}$ = 9 tìm x

2 bình luận về “$( 2x + 1)^{2}$ – 4 $(x – 1)^{2}$ = 9 tìm x”

1. (2*x+1)^2 -4*(x-1)^2 = 9

   ⇔(2x+1)^2-4(x-1)^2=3(4x-1)

   ⇔3(4x-1)=3^2

   ⇔12x-2=9

   ⇔12x=12

   ⇔x=1

   vậy x=1

    

   Trả lời
2. (2x+1)^2-4.(x-1)^2=9

   =>(2x+1)^2-[2.(x-1)]^2=9

   =>(2x+1)^2-(2x-2)^2=9

   =>(2x+1-2x+2).(2x+1+2x-2)=9

   =>3.(4x-1)=9

   =>4x-1=3

   =>4.x=4

   =>x=1

   Vậy  x=1

    

   Trả lời