(20a^2)/(4a+5)*5a при a=-3
20a²/(4a+5)5a=20a²/(20a²+25a)=1/25a=0,04a a=-3 -3*0,04=-0,12
20a^2/(4a+5)*5=20a^2/20a^2+25a=1/25a=1/-75