Respuesta :

Given: y²+5y
Converting y²+5y in the form: x²+2ax+a²
Here 2a=5 or a=5/2
Add and subtract (5/2)²
y²+5y+(5/2)²-(5/2)²   
Complete the square.
(y+5/2)²-(5/2)²
Simplify
(y+5/2)² - 25/4

Answer: (y+5/2)² - 25/4