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: x mũ2+2x-15=0 2x+3xy (x-y) mũ 3

Home/ Toán Lớp 8: x mũ2+2x-15=0 2x+3xy (x-y) mũ 3

Toán Lớp 8: x mũ2+2x-15=0 2x+3xy (x-y) mũ 3

Tháng Bảy 29, 2022 Toán học 1 Comment 0 views

Toán Lớp 8: x mũ2+2x-15=0
2x+3xy
(x-y) mũ 3

Comments ( 1 )

  1. phuongthaongoc
    phuongthaongoc
    29 Tháng Bảy, 2022 at 9:25 sáng
    Reply
    x^2 + 2x – 15 = 0
    => x^2 – 3x + 5x – 15 = 0
    => ( x^2 – 3x ) + ( 5x – 15 ) = 0
    => x ( x – 3 ) + 5 ( x – 3 ) = 0
    => ( x – 3 )( x + 5 ) = 0
    => \(\left[ \begin{array}{l}x-3=0\\x+5 = 0\end{array} \right.\) 
    => \(\left[ \begin{array}{l}x=3\\x=-5\end{array} \right.\) 
    Vậy x $\in$ { 3 ; -5 }  
    b) 2x + 2xy  
    = 2x ( 1 + y )
    c) ( x – y )^3
    = x^3 – 3.x^2.y + 3.x.y^2 – y^3
    = x^3 – 3x^2y + 3xy^2 – y^3  

Leave a reply

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

Ngọc Ðàn

About Ngọc Ðàn