fill in the blanks so that the left side is a perfect square

fill in the blanks so that the left side is a perfect square trinomial; that is, complete the square. y^2-7y+_=(y-_)^2

First we use the standard formula : (a - b)^2 = a^2 +b^2 -2ab

We are given :y^2-7y+_=(y-_)^2

Lets compare with standard formula terms: a =y ;

2ab =-7y ; so, 2*y*b = -7y

we get b= 7/2

So, missing term on LHS : b^2 = (-7/2)^2 = 49/4

On RHS missing term : b = 7/2

So, y^2 - 7y + 49/4_=(y - 7/2)^2