How do I complete the square?
X^2+14x+_____

Question

How do I complete the square?
X^2+14x+_____

anonymous · Answer

x(x+14)
x=0 x=-14 
am i right ? sorry, if i made mistakes.

anonymous · Answer

Hmm, no. On the reveiw answer sheet she gave 14 • 1/2=(7)^2=49 I just don't remember how to work it...

zehanz · Answer

Remember that (a + b)² = a² + 2ab + b².
If you see x² + 14x + ... as the result of this rule, it has to be
(x + 7)², because

(x + 7)² = x² + 14x + 49. 

14x is 2*x*7, just as in the 2ab term.
That is why you know it has to be x + 7.

7² = 49 is the last term, same as the b².
So 49 completes the square.

Hope this helps!

ZeHanz.