Answer:
[tex]\frac{1}{4}[/tex]
Step-by-step explanation:
Let us see the standard form of an quadratic equation converted form of complete square .
[tex](a+b)^2=a^2+2*a*b+b^2[/tex]
The first two terms given are
[tex]y^2+y\\=y^2+2*\frac{1}{2}*y[/tex]
Hence comparing it with our standard form
The constant term must be the square of the middle term. That it [tex](\frac{1}{2})^2=\frac{1}{4}[/tex]