1:(x²+1)y²-x²-1 2:-49x²+14x-1+y²

1:(x²+1)y²-x²-1 2:-49x²+14x-1+y²

하나:(x&\#178;+1)y²-x²-1=x²y²-x²+y²-1=x²(y²-1)+(y²-1)
=(x²-1)(y²-1)=(x+1)(x-1)(y+1)(y-1)
2:-49x&\#178;+14x-1+y²
=y²-(49x²-14x+1)=y²-((7x)²-14x+1)
=y²-(7x-1)²
=(y+7x-1)(y-7x+1)