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: Tính: a, (2x+1) ²-(x-3)(x+3) b, (x-3y)(x+3y) + (x-y) ² c, (x-2)(x+2)-x(x+3) Giúp mk vs nha

Toán Lớp 8: Tính:
a, (2x+1) ²-(x-3)(x+3)
b, (x-3y)(x+3y) + (x-y) ²
c, (x-2)(x+2)-x(x+3)
Giúp mk vs nha

Comments ( 2 )

  1. a, (2x+1) ²-(x-3)(x+3)
    = (2x+1) ²-(x²-3²)
    = 4x²+4x+1-x²+9
    = 3x²+4x+10
    b, (x-3y)(x+3y) + (x-y) ²
    =x²-9y²+x²-2xy+y²
    = 2x²-8y²-2xy
    c, (x-2)(x+2)-x(x+3)
    =x²-4-x²-3x
    = -4-3x

  2. Giải đáp+Lời giải và giải thích chi tiết:
    a)
    $(2x+1)^2$-(x-3)(x+3)
    =$4x^2$+4x+1-$x^2$+9
    =$3x^2$+4x+10
    b)
    (x-3y)(x+3y)+$(x-y)^2$
    =$x^2$-$9y^2$+$x^2$-2xy+$y^2$
    =$2x^2$$-8y^2$-2xy
    c)
    (x-2)(x+2)-x(x+3)
    =$x^2$-4-$x^2$-3x
    =-3x-4

Leave a reply

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