原式
=(x^4-4x²y²+4y^4)-(2x²-4y²)-24
=(x²-2y²)²- 2(x²-2y²)-24
=(x²-2y²-6)(x²-2y²+4)
原式=(X^2-2Y^2 )^2-2(X^2-2Y^2 )-24
=(X^2-2Y^2-6)(X^2-2Y^2+4)
x^4-2x^2(y^2+2)+y^4+4y^2+3
=x^4-2x²y²+y^4-4x²+4y²+3
=(x²-y²)²-4(x²-y²)+3
=(x²-y²-1)(x²-y²-3)
{(X^2-2Y^2 )^2-2(X^2-2Y^2 )+1}-5^2
=(X^2-2Y^2-1)^2-5^2
=(X^2-2Y^2+4)(X^2-2Y^2-6)