in the function f(x)=4(x^2-6x+ )+20 what number will complete the square

Answer 1

I would multiply 4 in to get 4x^2-24x+20
Then factor out 4 4(x^2-6x+5)
Complete the square inside the bracket 4[(x-3)^2-9+5] = 4[(x-3)^2 -4]= 4(x-3)^2 -16
I would think it is +16 needed to complete the square

Answer 2

f(x) = 4(x^2 - 6x + 9 - 9) + 20
= 4( (x-3)^2 - 9) + 20
= 4(x-3)^2 - 36 + 20
= 4(x-3)^2 - 16