Question

How can I make this a perfect square
w^2-4w+

Answer 1

ax^2+bx+c
if a=1, then
take 1/2 of b and square it

w^2-4w+c
b=-4
-4/2=-2, (-2)^2=4
add that
w^2-4w+4
(w-2)(w-2)
(w-2)^2

to make it into perfect squres, add 4