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

Toán Lớp 8: ( x – 3 ) . ( x + 3 ) . ( x + 2 ) – ( x – 1 ) . ( x^2 – 3 ) – 5x . ( x + 4 )^2 – ( x – 5 )^2 2x . ( n – 4 )^2 – ( x + 5 ) . ( x – 2 )

Tháng Bảy 29, 2022 Toán học 1 Comment 0 views

Toán Lớp 8: ( x – 3 ) . ( x + 3 ) . ( x + 2 ) – ( x – 1 ) . ( x^2 – 3 ) – 5x . ( x + 4 )^2 – ( x – 5 )^2
2x . ( n – 4 )^2 – ( x + 5 ) . ( x – 2 ) . ( x + 2 ) + 2 ( x + 5 )^2 – ( x – 1 )^2

Comments ( 1 )

  1. doanthulan
    doanthulan
    29 Tháng Bảy, 2022 at 3:12 sáng
    Reply
    Giải đáp:
     
    Lời giải và giải thích chi tiết:
    ( x – 3 ) . ( x + 3 ) . ( x + 2 ) – ( x – 1 ) . ( x² – 3 ) – 5x . ( x + 4 )² – ( x – 5 )²
    = ( x² – 3² ) . ( x + 2 ) – [ x . x² + x . ( – 3 ) – 1 . x² – 1 . ( – 3 ) ] 
    =  ( x² – 9 ) . ( x + 2 ) – ( x³ – 3x – x² + 3 ) 
    = ( x² . x + x² . 2 – 9 . x – 9 . 2 ) – x³ + 3x + x² – 3
    = x³ + 2x² – 9x – 18 – x³ + 3x + x² – 3
    = ( x³ – x³ ) + ( 2x² + x² ) + ( – 9x + 3x ) + ( – 18 – 3 )
    = 3x² – 6x – 21
    2x . ( n – 4 )² – ( x + 5 ) . ( x – 2 ) . ( x + 2 ) + 2 ( x + 5 )² – ( x – 1 )²
    = 2x . ( n² – 2 . n . 4 + 4² ) – ( x + 5 ) . ( x² – 2² ) + 2 ( x² + 2 . x . 5 + 5² ) – ( x² – 2 . x . 1 + 1² )
    = 2x . ( n² – 8n + 16 ) –  ( x + 5 ) . ( x² – 4 ) + 2 ( x² + 10x + 25 ) – ( x² – 2x + 1 )
    = 2x . ( n² – 8n + 16 ) –  ( x + 5 ) . ( x² – 4 ) + 2 ( x² + 10x + 25 ) – x² + 2x – 1 
    = 2x . n² + 2x . ( – 8n ) + 2x . 16 – [ x . x² + x . ( – 4 ) + 5 . x² + 5 . ( – 4 ) ] – x² + 2x – 1 
    = 2n²x – 16nx + 32x – ( x³ – 4x + 5x² – 20 ) – x² + 2x – 1
    =  2n²x – 16nx + 32x – x³ + 4x – 5x² + 20  – x² + 2x – 1
    =  2n²x – 16nx + 32x – x³ + ( – 5x² – x² ) + ( 4x + 2x ) + ( 20 – 1 )
    = 2n²x – 16nx + 32x – x³ – 6x² + 6x  + 19

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

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