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

Toán Lớp 8: `x^2 -5x+6` `(9x^3 -27x): 9x – (x-4)^2 =16`

Toán Lớp 8: x^2 -5x+6
(9x^3 -27x): 9x – (x-4)^2 =16

Comments ( 2 )

  1. Giải đáp:
    1,
    x^2−5x+6
    =x^2−2x−3x+6
    =x.(x−2)−3.(x−2)
    =(x -2).(x – 3)
    —————–
    2,
    (9x^3−27x):9x−(x−4)^2=16
    ↔ [(9x^3:9x)−(27x:9x)]− (x^2−2x.4+4^2)=16
    ↔ x^2−3−(x^2−8x+16)=16
    ↔ x^2−3−x^2+8x−16=16
    ↔ (x^2−x^2)+8x−(16+3)=16
    ↔ 8x−19=16
    ↔ 8x=35
    ↔ x = 35/8
    Vậy x = 35/8
    #dariana

  2. Giải đáp+Lời giải và giải thích chi tiết:
    x^2-5x+6
    =x^2-2x-3x+6
    =(x^2-2x)-(3x-6)
    =x(x-2)-3(x-2)
    =(x-3)(x-2)
    (9x^3-27x):9x-(x-4)^2=16
    <=> 9x^3:9x-27x:9x-(x^2-2x.4+4^2)=16
    <=> x^2-3-(x^2-8x+16)=16
    <=> x^2-3-x^2+8x-16=16
    <=> (x^2-x^2)+8x-(16+3)=16
    <=> 8x-19=16
    <=> 8x=16+19
    <=> 8x=35
    <=> x=35/8
    Vậy x=35/8 

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