Объяснение:
(y^2-6y+9)/(y^2+3y):
:(10y-30)/(y^2+3y)=
=((y-3^2)/(y-3)(y+3))×(y(y+3)/10(y-3))=
=y/10=70/10=7
у^2-6у+9/у^2-9÷10у-30/у^2+3у=4900-420+9/70^2-63-30/70^2+210=4627+9/4900-30/4900=22672309/4900-30/4900=3238897/700=4626целых 697/700
