（3ab^3-6a^2b^2）除以（2a-b)计算

【5】(1/3a^2b^3)·(-15a^2b^2)=-5a^4b^5
【6】(4a^3b-6a^2b^2+12ab^3)÷(2ab)
=4a^3b÷(2ab)-6a^2b^2÷(2ab)+12ab^3÷(2ab)=2a^2-3ab+6b^2
【7】(a^2bc)^2÷(ab^2c) =a^4b^2c^2÷(ab^2c) = a^3c
【8】(3mn+1)(3mn-1)-8m^2n^2 =9m^2n^2-1-8m^2n^2=m^2n^2-1
【9】[(3a+b)^2-b^2]÷a =(9a^2+6ab+b^2-b^2)÷a =a(9a+6b)÷a =9a+6b
【10】(x+2)^2-(x+1)(x-1)=x^2+4x+4-x^2+1=4x+5

(1).-4x²+10x=-2x(2x-5)
(2).3y^2-5xy-y=y(3y-5x-1)
(3)15a³b-21a²b³+6a²b²=3ab(5a²-7ab²+2ab)

设三角形的面积S＝4a^3b-6a^2b^2 + 12ab^2,l = 4ab
根据三角形的面积公式 S ＝（1/2) lh可得
h = 2S/l = (2(4a^3b - 6a^2b^2 + 12ab^2)/4ab
= (8a^3b^2 - 12a^2 b^2 + 24ab^2)/4ab
= 2a^2b - 3ab + 6b
故所求的高为 2a^2b -3ab + 6

1.原式=[2ab(2a-3ab+6b)]/2ab=2a-3ab+6b
2.原式=x^2+4x+4-(x^2-1)=x^2+4x+4-x^2+1=4x+5
3.原式=(2000+1)^2=2000^2+2*2000*1+1^2=4000000+4000+1=4004001
4.原式=99^2-1^2=(99+1)(99-1)=100*98=9800
5.原式=(2000+1)-(2000-1)=2000+1-2000+1=2
6.原式=(x^2-y^2)-(x^2-2xy+y^2)+4y^2=x^2-y^2-x^2+2xy-y^2+2y^2=2xy
x=3,2y=3,原式=2y*x=3*3=9
7.(1)=(a^2-2ab+b^2)+(a^2+2ab+b^2)=2a^2+2b^2
(2)=4/1[(a^2+2ab+b^2)-(a^2-2ab+b^2)]=4/1[(a+b)^2-(a-b)^2]=4/1[(a+b)+(a-b)][(a+b)-(a-b)]=4/1*2a*2b=4/1*4ab=ab
(3)C=3B-2A=3(a^2+2ab+b^2)-2(a^2-2ab+b^2)=3a^2+6ab+3b^2-2a^2+4ab-2b^2=a^2+10ab+b^2
请看在回答的份上 点一下右下角大拇指"赞同"送我1分 =3=】

3a^3b-6a^2b^2+9ab^3
=3ab(a^2-2ab+3b^2)

M=[(4ab^3-6a^2b^2-12a^3b^2+b^4)-b^4]除以2ab
=2b^2-3ab-6a^2b
纯手打,求采纳,

4+b^4>=2a^2b^2 {公式（ 因为a^2+b^2-2ab=(a+b)^2>=0 所以 a^2+b^2>=2ab}
2a^3b+2ab^3>=2根号a^3b*2根号ab^3=4a^2b^2
把两个不等式相加
a^4+2a^3b+2ab^3+b^4>=6a^2b^2

(4a^3b-6a^2b^2+12ab^3)
2ab(2a^2-3ab+6b^2)
除个2ab
就等于2a^2-3ab+6b^2

2ab+3c^2

(1).-4x²+10x=-2x(2x-5)
(2).3y^2-5xy-y=y(3y-5x-1)
(3)15a³b-21a²b³+6a²b²=3ab(5a²-7ab²+2ab)

证明：
a^4+b^4>=2a^2b^2 {公式（ 因为a^2+b^2-2ab=(a+b)^2>=0 所以 a^2+b^2>=2ab}
2a^3b+2ab^3>=2根号a^3b*2根号ab^3=4a^2b^2
把两个不等式相加
a^4+2a^3b+2ab^3+b^4>=6a^2b^2

因为(m-1/2)^2+1/3乘n-2的绝对值=0
且(m-1/2)^2≥0,n-2的绝对值≥0,
所以m-1/2=0,n-2=0,
所以m=1/2,n=2,
这个多项式就是
(2a^2mb^n)(2a^3b^2-6a^2b^2+4ab^2)
=(2ab^2)(2a^3b^2-6a^2b^2+4ab^2)
=4a^4b^4-12a^3b^4+8a^2b^4.

7a^2b^2+1
a^2b^2+1

2-18a^4 分之 6a^2b^2-2b^2
=(6a^2b^2-2b^2)/(2-18a^4)
=2b^2(3a^2-1)/2(1-9a^4)
=b^2(3a^2-1)/(1+3a^2)(1-3a^2)
=-b^2/(1+3a^2)

M=[(4ab^3-6a^2b^2-12a^3b^2+b^4)-b^4]除以2ab
=2b^2-3ab-6a^2