Question

How do we find the number to make the perfect square?

Answer 1

For any two non null real numbers a and b, a perfect square can be represented by:

$(a+b)^2=a^2+2ab+b^2$

Then, if a = y, we must find a number b such as:

$2yb=4y$

Then, b = 2, and b² = 4

Therefore:

$y^2+4y+2^2$