well, 6^2 = 36
So, you want (x+6)^2 = x^2 + 12x + 36
recall that (x+a)^2 = x^2 + 2ax + a^2
Complete the square.
x^2 + _____ + 36
Help me? I don't understand.
2 answers
well, 36 = 6^2 so try
x^2 + b x + 36 = (x+6)^2
x^2 + b x + 36 = x^2 + 12 x + 36
so
x^2 + 12 x + 36
-------------------
more officially
(b/2)^2 = 36
b/2 = 6
b = 12
x^2 + b x + 36 = (x+6)^2
x^2 + b x + 36 = x^2 + 12 x + 36
so
x^2 + 12 x + 36
-------------------
more officially
(b/2)^2 = 36
b/2 = 6
b = 12