Question

x²-1（xy)²-13x²+6xy+3y²（x-y）²+4xy(a+

Answer 1

x²-1=(x+1)(x-1)

（xy)²-1=(xy+1)(xy-1)

3x²+6xy+3y²=3(x+y)^2

（x-y）²+4xy=(x+y)^2

(a+b)²+2(a+b)+1=(a+b+1)^2

x³-25x=x(x+5)(x-5)