''V''=radical
1/(3-V2-V5)=[(3-V2)+V5]/{[(3-V2)-V5]*[(3-V2)+V5]=
=(3-V2+V5)/[(3-V2)^2-5]=
=(3-V2+V5)/(9-6V2+2-5)=
=(3-V2+V5)/(6-6V2)=
(3-V2+V5)/6(1-V2)=
=(3-V2+V5)(1+V2)/6(1-V2)(1+V2)=
=(3+3V2-V2-2+V5+V10)/6(1-2)=
=(1+2V2+V5+V10)/(-6)=
=-(1+2V2+V5+V10)/6
