2y^2 +4y+2=0

2y^2 +4y+2=0

2(y^2+2y+1)=0

2 (y )(y ) ( +1)( +1)

2 (y+1)(y+1)=2(y+1)^2

Check:

2 (y+1)(y+1)

2 (y)(y) (y)(1) (1)(y) (1)(1)

2 (y^2 +y +1 +1)

2 (y^2+2y+1)