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

Toán Lớp 8: Phân tích đa thức thành nhân tử a) x3 + 2x – 3 b) x3 – 7x + 6 c) x3 + 5×2 + 8x + 4 d) x3 – 9×2 + 6x + 16

Toán Lớp 8: Phân tích đa thức thành nhân tử
a) x3 + 2x – 3
b) x3 – 7x + 6
c) x3 + 5×2 + 8x + 4
d) x3 – 9×2 + 6x + 16

Comments ( 2 )

  1. Giải đáp + Lời giải và giải thích chi tiết:
    $#hyn$
    $a)x^3+2x-3$
    $=x^3-x^2+x^2-x+3x-3$
    $=x^2(x-1)+x(x-1)+3(x-1)$
    $=(x-1)(x^2+x+3)$
    $b)x^3-7x+6$
    $=x^3-x^2+x^2-x-6x+6$
    $=x^2(x-1)+x(x-1)-6(x-1)$
    $=(x-1)(x^2+x-6)$
    $=(x-1)(x^2-2x+3x-6)$
    $=(x-1)[x(x-2)+3(x-2)]$
    $=(x-1)(x-2)(x+3)$
    $c)x^3+5x^2+8x+4$
    $=x^3+x^2+4x^2+4x+4x+4$
    $=x^2(x+1)+4x(x+1)+4(x+1)$
    $=(x+1)(x^2+4x+4)$
    $=(x+1)(x+2)^2$
    $d)x^3-9x^2+6x+16$
    $=x^3+x^2-10x^2-10x+16x+16$
    $=x^2(x+1)-10x(x+1)+16(x+1)$
    $=(x+1)(x^2-10x+16)$
    $=(x+1)(x^2-2x-8x+16)$
    $=(x+1)[x(x-2)-8(x-2)]$
    $=(x+1)(x-2)(x-8)$
     

  2. Giải đáp
    $a) (x-1)(x^2+x+3)$
    $b) (x-1)(x-2)(x+3)$
    $c) (x+1)(x+2)^2$
    $d) ( x + 1 ) ( x – 2 ) ( x – 8 )$
    Lời giải và giải thích chi tiết:
    $a)x^3+2x-3$
    $=x^3-x^2+x^2-x+3x-3$
    $=x^2(x-1)+x(x-1)+3(x-1)$
    $=(x-1)(x^2+x+3)$
    $b)x^3-7x+6$
    $=x^3-x^2+x^2-x-6x+6$
    $=x^2(x-1)+x(x-1)-6(x-1)$
    $=(x-1)(x^2+x-6)$
    $=(x-1)(x^2-2x+3x-6)$
    $=(x-1)[x(x-2)+3(x-2)]$
    $=(x-1)(x-2)(x+3)$
    $c)x^3+5x^2+8x+4$
    $=x^3+x^2+4x^2+4x+4x+4$
    $=x^2(x+1)+4x(x+1)+4(x+1)$
    $=(x+1)(x^2+4x+4)$
    $=(x+1)(x+2)^2$
    $d)x^3-9x^2+6x+16$
    $=x^3+x^2-10x^2-10x+16x+16$
    $=x^2(x+1)-10x(x+1)+16(x+1)$
    $=(x+1)(x^2-10x+16)$
    $=(x+1)(x^2-2x-8x+16)$
    $=(x+1)[x(x-2)-8(x-2)]$
    $= ( x + 1 ) ( x – 2 ) ( x – 8 )$

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

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