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: 2 rút gọn a) (x+2)^2+2(x+1)=12 b) (x+2)^2-(x-2) (x+1)=3

Tháng Hai 22, 2023 Toán học 0 Comments 0 views

Toán Lớp 8: 2 rút gọn
a) (x+2)^2+2(x+1)=12
b) (x+2)^2-(x-2) (x+1)=3

Comments ( 2 )

  1. giangnguyen33
    giangnguyen33
    22 Tháng Hai, 2023 at 7:23 sáng
    Reply

    .
    toan-lop-8-2-rut-gon-a-2-2-2-1-12-b-2-2-2-1-3

  2. kimoanh34
    kimoanh34
    22 Tháng Hai, 2023 at 7:22 sáng
    Reply
    a) (x+2)^2+2(x+1)=12
    ⇔ x^2+4x+4+2x+2=12
    ⇔ x^2+4x +2x=12-2-4
    ⇔ x^2+6x-6=0
    ⇔ x^2+6x+9-9-6=0
    ⇔ (x+3)^2-15=0
    ⇔ (x+3)^2=15
    ⇔x+3=± \sqrt15
    ⇔x=-3±\sqrt15 
    Vậy S={-3+\sqrt15 ;-3-\sqrt15 }
    b) (x+2)^2-(x-2) (x+1)=3
    ⇔x^2+4x+4-(x^2+x-2x-2)-3=0
    ⇔x^2+4x+4-x^2-x+2x+2-3=0
    ⇔ 5x=-3
    ⇔x=\frac{-3}{5}
    Vậy S={$\dfrac{-3}{5}$}

Leave a reply

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

Thanh Tú

About Thanh Tú