(6a-4b-5ab)-(4a-6b 7ab)

(2-ab+2a+5b)-(3ab+2b-2a)-(3a+4b-ab)=2-ab+2a+5b-3ab-2b+2a-3a-4b+ab=a-b-4ab+2=4-4+2=2

1.(a-b+4ab/a-b)(a+b-4ab/a+b)=(a-b+4b-a)(a+b-4b+a)=3b*(-3b)=-9b^2此题是否为[a-b+4ab/（a-b)][a+b-4ab/(a+b)]=

a-(3ab+b)+(3a-4b-ab)=a-3ab-b+3a-4b-ab=4a-4ab-5

原式=5a²b(a-b)-3ab(a-b)²-5ab²(a-b)=ab(a-b)[5a-3(a-b)-5b]=ab(a-b)(5a-3a+3b-5b)=ab(a-b)(2

(2a+3b-2ab)-(a+4b+ab)-(3ab-2a+2b)=2a+3b-2ab-a-4b-ab-3ab+2a-2b=3a-3b-5ab=3(a-b)-5ab=3x5-5x(-5)=40

5ab+4a+7b+6a-3ab-4ab+3b=(5-3-4)ab+(4+6)a+(7+3)b=10a+10b-2ab=10(a+b)-2ab=10×6-2×3=54

2(2A+B)-3(A+B)=4A+2B-3A-3B=A-B=5a^3b+2a^4-3a^2b-ab^3-(6ab^3-8a^3b+3a^4-5b^4)=-a^4+13a^3b-3a^2b-7ab^3

(5ab+4a+7b)+(6a-3ab)-(4ab-3b)=5ab+4a+7b+6a-3ab-4ab+3b=-2ab+10a+10b=-2ab+10(a+b)∵a+b=17,ab=10∴原式=-2×1

(5a-5b-ab)-(4a-6b-3ab)=5a-5b-ab-4a+6b+3ab=a+b+2ab=3-2x2=-1

（22a+3b-2ab)-(a+4b+ab)-(3ab+2b-2a)=22a+3b-2ab-a-4b-ab-3ab-2b+2a=23a-3b-5ab题目抄差了!（22a+3b-2ab)应该是（2a+3

∵a+b=3，ab=-2，（4a-5b-3ab）-（3a-6b+ab）=4a-5b-3ab-3a+6b-ab=a+b-4ab=3-4×（-2）=11，故答案为：11．

题目最后一项应该为4b²a²+5ab+4b²=(a+4b)(a+b)

2A+4+3AB+6B=A(2+3B)+2(2+3B)=(2+3B)(A+2)

(2a+5b-3ab)-(a+6b-ab)-(2ab+2b-2a)=2a+5b-3ab-a-6b+ab-2ab-2b+2a=3a-3b-4ab=3(a-b)-4ab=12-12=0

(3a-2b)(3a+2b)(3a+2b)-(3a+2b)(3a-2b)(3a-2b)=(3a-2b)(3a+2b)4

-5a^2b+6ab^2-4ab-2a^2b+4ab+3=-5a^2b-2a^2b+6ab^2-4ab+4ab+3=(-5-2)a^2b+6ab^2+3=-7a^2b+6ab^2+36x+2x^2-3

（1）6x＋2x－3x＋x＋1＝6x＋1其中x＝5原式＝30＋1＝31（2）1／3m-3/2n-5/6n-1/6m＝1／6m－14／6n＝6／1m－7／3n其中m＝6,n＝3原式＝1－7＝－6第二题一

(4a^2+3ab-b^2)-(7a^2-5ab+2b^2)=-3a^2+8ab-3b^2=-3(a^2+2ab+b^2)+8ab+6ab=-3(a+b)^2+14ab=-3*6^2+14*(-2)=

原式=5ab+4a+7b+6a-3b-4ab-6a=4a+4b+ab=4(a+b)+ab=4×7+10=38M=(a-b+c)-(a-b-c)=a-b+c-a+b+c=2cx-2y=3所以原式=1-2