-49x²+14x-1+y²

问题描述:

-49x²+14x-1+y²
分解因式

-49x²+14x-1+y²
=y²-(49x²-14x-1)
=y²-(7x-1)²
=[y+(7x-1)][y-(7x-1)]
=(y+7x-1)(y-7x+1)