因式分解:(1)-1+(9/49x²) (2)-2x²+2xy-(1/2y²)

问题描述:

因式分解:(1)-1+(9/49x²) (2)-2x²+2xy-(1/2y²)

(1)-1+(9/49x²)
=9/49x²-1
=(3/7x+1)(3/7x-1)
(2)-2x²+2xy-(1/2y²)
=-1/2(4x²-4xy+y²)
=-1/2(2x-y)²