(х+2)/(х-2)- х/(2-х)=(х+2)/(х-2)- х/ -(-2+х)=(х+2)/(х-2)+х/ (х-2)=(х+2+х)/()х-2=
=(2х+2)/(х-2)=2(х+1) /(х-2)
(4b+7c)/(3b-2c)- (2b+3c)/(2c-3b)= (4b+7c)/(3b-2c)+(2b+3c)/(3b-2c)=
=(4b+7c+2b+3c) /(2c-3b)=(9b+10c)/ (2c+3b)
a²/(3a-18) + 3b/(18-3a) = (a²-3b)/(3a-18)