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: phân tíchđa thứ thành câu hỏi 1) x^2-6x-y^2+9 2) x^2-2xy+2x-4y 3)x^2-y^2+2x+1 4)x^3-4x 5)2x^2-6xy+5x-15

Toán Lớp 8: phân tíchđa thứ thành câu hỏi
1) x^2-6x-y^2+9
2) x^2-2xy+2x-4y
3)x^2-y^2+2x+1
4)x^3-4x
5)2x^2-6xy+5x-15

Comments ( 2 )

  1. 1)
    x^2-6x-y^2+9
    =(x^2-6x+9)-y^2
    =(x-3)^2-y^2
    =(x-3-y)(x-3+y)
    2)
    x^2-2xy+2x-4y
    =(x^2+2x)-(2xy+4y)
    =x(x+2)-2y(x+2)
    =(x-2y)(x+2)
    3)
    x^2-y^2+2x+1
    =(x^2+2x+1)-y^2
    =(x+1)^2-y^2
    =(x+1-y)(x+1+y)
    4)
    x^3-4x
    =x(x^2-4) 
    =x(x^2-4x+4)
    5)
    *sửa đề: sửa 15 thành 15y 
    2x^2-6xy+5x-15y
    =(2x^2-6xy)+(5x-15y)
    =2x(x-3y)+5(x-3y)
    =(2x+5)(x-3y) 

  2. 1,
    $x^2-6x-y^2+9$
    $=(x-3)^2-y^2$
    $=(x-3+y)(x-3-y)$
    2,
    $x^2-2xy+2x-4y$
    $=x(x-2y)+2(x-2y)$
    $=(x+2)(x-2y)$
    3,
    $x^2-y^2+2x+1$
    $=(x+1)^2-y^2$
    $=(x+1-y)(x+1+y)$
    4,
    $x^3-4x$
    $=x(x^2-4)$
    $=x(x-2)(x+2)$
    5,
    Thêm y
    $2x^2-6xy+5x-15y$
    $=x(2x+5)-3y(2x+5)$
    $=(x-3y)(2x+5)$

Leave a reply

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

About Thu Giang