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 – 3y ) ^3 – ( 2x – y ) . ( 3x + 2y) . ( 3x – 2y ) 2x^2 . ( x – 2 ) + 3x . ( x^2 – x – 2 ) – 15 + 5x^2 ( x – 2 )^2 + ( x + 3 )^2 – (

Home/ Toán Lớp 8: (x – 3y ) ^3 – ( 2x – y ) . ( 3x + 2y) . ( 3x – 2y ) 2x^2 . ( x – 2 ) + 3x . ( x^2 – x – 2 ) – 15 + 5x^2 ( x – 2 )^2 + ( x + 3 )^2 – (

Toán Lớp 8: (x – 3y ) ^3 – ( 2x – y ) . ( 3x + 2y) . ( 3x – 2y ) 2x^2 . ( x – 2 ) + 3x . ( x^2 – x – 2 ) – 15 + 5x^2 ( x – 2 )^2 + ( x + 3 )^2 – (

Tháng Bảy 29, 2022 Toán học 2 Comments 0 views

Toán Lớp 8: (x – 3y ) ^3 – ( 2x – y ) . ( 3x + 2y) . ( 3x – 2y )
2x^2 . ( x – 2 ) + 3x . ( x^2 – x – 2 ) – 15 + 5x^2
( x – 2 )^2 + ( x + 3 )^2 – ( 2x + 1 ) ( x – 1 )

Comments ( 2 )

  1. cattien
    cattien
    29 Tháng Bảy, 2022 at 4:19 sáng
    Reply
    \text{a)} (x – 3y)^3 – (2x – y) . (3x + 2y) . (3x – 2y)
    = x^3 – 3. x^2. 3y + 3. x. 3y^2 – (3y)^3 – (2x – y) . (3x)^2 . (2y)^2
    = x^3 – 9x^2y + 9xy^2 – 27y^3 – 18x^3 – 8xy^2 – 9x^2y – 4y^3
    = (x^3 – 18x^3) + (- 9x^2y – 9x^2y) + (9xy^2 – 8xy^2) + (- 27y^3 – 4y^3)
    = – 17x^3 – 18x^2y + xy^2 – 31y^3
    \text{b)} 2x^2 . (x – 2) + 3x . (x^2 – x – 2) – 15 + 5x^2
    = 2x^3 – 4x^2 + 3x^3 – 3x^2 – 6x – 15 + 5x^2
    = (2x^3 + 3x^3) + (- 4x^2 – 3x^2 + 5x^2) – 6x – 15
    = 5x^3 – 2x^2 – 5x – 15
    \text{c)} (x – 2)^2 + (x + 3)^2 – (2x + 1) (x – 1)
    = x^2 – 2. x. 2 + 2^2 + x^2 + 2. x . 3 + 3^2 – 2x^2 + 2x – x + 1
    = x^2 – 4x + 4 + x^2 + 6x + 9 – 2x^2 + x + 1
    = (x^2 + x^2 – 2x^2) + (- 4x + 6x + x) + (4 + 9 + 1)
    = 3x + 14

  2. ngocle44
    ngocle44
    29 Tháng Bảy, 2022 at 4:18 sáng
    Reply
            (x – 3y ) ³ – ( 2x – y ) . ( 3x + 2y) . ( 3x – 2y )
    =x³-3x²3y+3x9y²-25y³-(2x-y)(9x²-4y)
    =x³-9x²y+27xy²-25y³-(18x³-8xy-9x²y+4y²)
    =x³-9x²y+27xy²-25y³-18x³+8xy+9x²y-4y²
    =-17x³-25y³+27xy²+8xy
          2x² . ( x – 2 ) + 3x . ( x² – x – 2 ) – 15 + 5x²
    =2x³-4x²+3x³-3x²-6x-15+5x²
    =5x³-2x²-6x-15
          ( x – 2 )² + ( x + 3 )² – ( 2x + 1 ) ( x – 1 )
    =x²-4x+4+x²+6x+9-(2x²-2x+x-1)
    =2x²+2x+13-2x²+2x-x+1
    =4x+14
    mình chưa kt lại nên …

Leave a reply

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

Băng

About Băng