Register Now

Login

Lost Password

Lost your password? Please enter your email address. You will receive a link and will create a new password via email.

222-9+11+12:2*14+14 = ? ( )

Toán Lớp 8: 3(x + 3) – x^2+9 giúp mình giải với ạ

Toán Lớp 8: 3(x + 3) – x^2+9 giúp mình giải với ạ

Comments ( 2 )

  1. Giải đáp:
     $3.(x+3)-x^2+9$
    $= 3.(x+3)-(x²-3²)$
    $= 3.(x+3)-(x-3).(x+3)$
    $= (x+3).(3-x+3)$
    $= (x+3).(6-x)$
     

  2. Cách 1 :
    3( x +3 ) – x^2 + 9
    = 3x + 9 – x^2 + 9
    = -x^2 + 3x + 18
    = -( x^2 – 3x – 18 )
    = -( x^2 + 3x – 6x – 18 )
    = -[x(x+3) – 6(x+3)]
    = -[(x+3)(x-6)]
    = -(x+3)(x-6)
    = (6-x)(x+3)
    Cách 2 :
    3( x +3 ) – x^2 + 9
    = 3( x + 3 ) – (x^2 – 3^2)
    = 3( x + 3 ) – (x-3)(x+3)
    = ( 3 – x + 3 )( x + 3 )
    = ( 6 – x )( x + 3 )
     

Leave a reply

222-9+11+12:2*14+14 = ? ( )

About Phương