1)20а²b-45by²=5b(4a²-9y²)=5b(2a-3y)(2a+3y) 3)0,3х³y-2,7xy³=0,3xy(x²-9y²)=0,3xy(x-9y)(x+3y) 5)108x⁷y⁵-4800x³y³=12x³y³(9x⁴y²-400)=3x³y³(3x²y-20)(3x²y+20)