Bài 5 a) 3x (x-2022) +x – 2022 = 0 b) x³ – 4x = 0 c) (2x – 1)² – 9 = 0

1 bình luận về “Bài 5 a) 3x (x-2022) +x – 2022 = 0 b) x³ – 4x = 0 c) (2x – 1)² – 9 = 0”

1. a) 3x.(x-2022)+x-2022=0

   =>3x.(x-2022)+1.(x-2022)=0

   =>(3x+1).(x-2022)=0

   =>[(3x+1=0),(x-2022=0):}

   =>[(x=-1/3),(x=2022):}

   Vậy x in {-1/3;2022}

   b) x^3-4x=0

   =>x.(x^2-4)=0

   =>x=0 hoặc x^2-4=0

   =>x=0 hoặc x^2=4

   =>x=0 hoặc x=+-2

   Vậy x in {0;2;-2}

   c)

   (2x-1)^2-9=0

   =>(2x-1)^2-3^2=0

   =>(2x-1-3).(2x-1+3)=0

   =>(2x-4).(2x+2)=0

   =>4.(x-2).(x+1)=0

   =>x-2=0 hoặc x+1=0

   =>x=2 hoặc x=-1

   Vậy x in {2;-1} 

    

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