С²+с-6=0
с1+с2=-1 U с1*с2=-6⇒c1=-3 U c2=2
1)2/(c-2)+(3c-21)/([(c-2)(c+3)]+2c/(c+3)=(2c+6+3c-21+2c²-4c)/[(c-2)(c+3)]=
=(2c²+c-15)/[(c-2)(c+3)]=2(c+3)(c-2,5)/[(c-2)(c+3)=(2c-5)/(c-2)
2c²+c-15=0
D=1+120=121
c1=(-1-11)/4=-3
c2=(-1+11)/4=2,5
2)(2c-5)/(c-2)*c/(2c-5)=c/(c-2)