1.（2a+3b-2ab)-(a+4b+ab)-(3ab+2b-2a)
=(2a-a+2a)+(3b-4b-2b)+(-2ab-ab-3ab)
=3a-3b-6ab
=3*5-6*1
=9
2.2m^2+13mn+6n^2-44
=2(m^2+2mn)+3(3mn+2n^2)-44
=2*13+3*21-44
=45
3.题目有误
4.a-2b/a+2b=4,所以a+2b/a-2b=1/4
3（a-2b)/4(a+2b)+3（a+2b）/a-2b
=3*(3/4)+3*(1/4)
=15/4
5.题目有误
6.x^2=1-x
x^3+3
=x*x^2+3
=x(1-x)+3
=x-x^2+3
=x-(1-x)+3
=2x+2
题目有误
7.x:y:z=3:4:5
那么(4x-5y+2z):(2x-y+z)=(12-20+10):(6-4+5)=2:7
2x-y-z=10*7/2=35
8.a/(abc+ab+a+1) +b/(bcd+bc+b+1)+ c/(cda+cd+c+1)+d/(dab+da+d+1)
=abcd/(bc+b+1+bcd)+b/(bc+bdc+b+1)+abcd/(da+d+1+abd)+d/(dab+da+d+1)
=(1+b)/(bcd+bc+b+1)+(1+d)/(abd+ad+d+1)
=(1+b)/(bcd+bc+b+1)+(1+d)bc/(b+1+bcd+bc)
=[(1+b)+(bc+bcd)]/(b+1+bcd+bc)
=1