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
