Which one is a factor of x2-y2+2y-1

Which one is a factor of x²-y²+2y-1

A x+y+1

B x-y+2xy

C x+y-1

D x-y-1

Solution

Correct Answer: Option C

x²- y²+ 2y - 1
= x²- (y²- 2y + 1)
= x²- (y - 1)²
= (x + y -1) (x - y +1)