Circle Equations help!!

[xxdumbledorexx]

Hi i was wondering what i was doing wrong for my question
x^2-8x+16+y^2-4y+4=29+16+4

The answer is supposed to be
Centre (4,2)
Radius 7

could you please guide me through the steps?
thank you

 

[HallsofIvy]

you know that (x- a)^2= x^2- 2ax+ a^2, don't you?

So what would (x- 4)^2 be equal to?
What would (y- 4)^2 be equal to?
What is 29+ 16+ 4?

Finally, do you know what the graph of (x- a)^2+ (y- b)^2= r^2 is?

(If you do not know those things, where did you get this problem?)