1.若 2x+y=0 ,则代数式4x^3+2xy[x+y]+y^3=[ ]

1个回答

  • 1:原式=4X^3+2X²Y+2XY²+Y^3

    =2X²(2X+Y)+Y²(2X+Y)

    =0

    2: 原式=1/2X^4Y^4+3X^5Y^4Z

    3: 原式=(3X^2+1/2Y-2/3Y^2)(-1/8X^3Y^3)

    =-3/8X^5Y^3-1/4X^3Y^4+1/12X^3Y^5

    4: 原式=24a^2b-9ab(a-b)+8ab^2

    =24a^2b-9a^2b+9ab^2+8ab^2

    =15a^b+17ab^2

    5: 原式=8a^6b^6-27a^6b^6+2a^2b^5+20ab^2

    =-19a^6b^6+2a^2b^5+20ab^2

    6: 原式=ab[ab^3(ab^2-1)-b]

    =ab[5ab^3-b]

    =ab(5ab^2-1)b

    =ab^2(5ab^2-1)

    =6*(5*6-1)

    =174

    7: 原式=x(x+y)^2-y(x+y)^2-3xy(x-y)

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

    =(x-y)[(x+y)^2-3xy]

    =-1/2[(3/2)^2-3*1/2]

    =3/4

    希望对你有用,如果错的话请见谅,因为我是口算的,有什么问题可加495294224