Question

What number must you add to complete the square?
x^2+8x=3

Answer 1

If you divide 8 by 2, you get what?

Answer 2

@skay 4

Answer 3

yup. so then if you factor that you get (x-4)^2
which covers your x squared but whats this, 4^2 isnt 8....

Answer 4

@skay 4^2 is 16

Answer 5

very good. now, what can you do with that 16.

Answer 6

@skay add 16

Answer 7

lol yea. but remember you have to add 16 to both sides. what you do to one side you have to do to the other,.

Answer 8

oh i made a mistake its (x+4)^2

Answer 9

also! just to make sure, you should have
x^2+8x+16=3+16
(x+4)^2=19
sqrt(x-4)^2)=sqrt(19)
x-4=sqrt(19)
x=4sqrt(19)

that's if you're solving for x though
x^2+8x+16 is a complete square.

Answer 10

you can use this method for completing any square. hope it helped!