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 10: Tìm x a) x’- 25x =0 b) x²-9=(2x+3)(x– 3) c) x’+x²+4=0

Toán Lớp 10: Tìm x a) x’- 25x =0 b) x²-9=(2x+3)(x– 3) c) x’+x²+4=0

Comments ( 2 )

  1. x^2-25x=0
    ⇔x(x-25)=0
    ⇔x=0 hoặc x-25=0⇒x=25
     b,
    x^2-9=(2x+3)(x-3)
    ⇔(x-3)(x+3)=2x^2+3x-6x-9
    ⇔x^2-9=2x^2-3x-9
    ⇔x^2-9-2x^2+3x+9=0
    ⇔-x^2+3x=0
    ⇔x(-x+3)=0
    ⇔x=0 hoặc -x+3=0⇒x=3

  2. Giải đáp:
    b) x2-9=(2x+3)(x– 3) 
    x^2 – 9 = 2x^2 – 6x + 3x – 9
    x^2 – 9 – 2x^2 + 3x + 9 = 0
    -x^2 + 3x = 0
    x(3 – x) = 0
    => x = 0 hoặc x = 3

Leave a reply

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

About Nhi