a)
-2-2a+3=-2+3-2a=1-2a
b)
2a-3b+3a-2b=2a+3a-3b-2b=5a-5b=5(a-b)
c)
2y-6y+4x-2x=2x-4y
d)
2x+3-6x-10=-4x-7
e)
-x+2x+(-6)+x-4=x+x-6-4=2x-10
f)
2ab-6-ab-(-3)=2ab-ab-6+3=ab-3
g) 3x^2-2y^2-6x^2-2y^2
3x^2-2y^2-6x^2-2y^2=3x^2-6x^2-2y^2-2y^2=-3x^2-4y^2
h)3,5b-2,4c-0,6c-0,5b
3,5b-2,4c-0,6c-0,5b=3,5b-0,5b-2,4c-0,6c=3b-3c=3(b-c)
i)3x^2-2x+1+x-4x^2-2
3x^2-2x+1+x-4x^2-2=3x^2-4x^2-2x+x+1-2=-x^2-x-1
j)2m^2+3mn-n+mn+3n-m^2
2m^2+3mn-n+mn+3n-m^2=2m^2-m^2+3mn+mn-n+3n=m^2+4mn+2n