3(y+5)^2-3y^2 СРОЧНО
Y(y-5)-3y(5-y)^2=0 y(y-5)-3y(y-5)^2=0 y(y-5)(1-3(y-5))=0 y(y-5)(1-3у+15)=0 у=0 или у=5 или -3у= -16: у= 16/3= 5 целых 1/3