用十字相乘法分解因式1)a^3-24a^2b+44ab^2 2)6x^2+23xy+20y^2 3)a^6-9a^3+8

2个回答

  • 1)a^3-24a^2b+44ab^2

    =a(a^2-24ab+44b^2)

    =a(a-22b)(a-2b)

    2)6x^2+23xy+20y^2

    =(2x+5y)(3x+4y)

    3)a^6-9a^3+8

    =(a^3-8)(a^3-1)

    =(a-2)(a^2+4a+4)(a-1)(a^2+a+1)

    =(a-2)(a^2+2a+4)(a-1)(a^2+a+1)

    4)a^4-21a^2-100

    =(a^2-25)(a^2+4)

    =(a+5)(a-5)(a^2+4)

    5)a^3-5a^2b-300ab^2

    =a(a^2- 5ab-300b^2)

    =a(a-20b)(a+15b)

    6)(x^2+2)^2-9x^2

    = (x^2+2+3x)(x^2+2-3x)

    = (x+1)(x+2)(x^2+2-3x)

    7)20x^2-39x+18

    =(4x-3)(5x-6)

    8)25x^2y^2-40xy+16

    =(5xy-4)^2

    9)a^2-4ab-12b^2

    =(a-6b)(a+2b)

    10)x^4+2x^2-3

    =(x^2-1)(x^2+3)

    =(x-1)(x+1)(x^2+3)

    11)3x^2-11x+10

    =(3x-5)(x-2)

    12)6x^2-11x-10

    =(3x+2)(2x-5)

    13)x^2-5x+6

    =(x-2)(x-3)