Find the number needed to complete the square of the expression: x^2+14x?

Question

Find the number needed to complete the square of the expression: x^2+14x?

Answer 1

To 'complete the square', take 1/2 of the number in front of the x (14) and square it.  So 1/2 of 14 is 7 and 7 squared is 49

x^2 + 14x + 49

Now, you can factor with the same factors

= (x + 7)(x + 7)

= (x + 7)^2

Answer: 49

Hope this helps you!  Please email for further clarification.

Answer 2

Write down some perfect square trinomials that have x^2 as the leading term.  Do you see any pattern ?  You should probably write down at least 5 or 6 expressions.  Look at the relationship between the coefficient b and the coefficient c.  If you don't understand my comments, then you should ask your teacher for help.  Read your book.

The answer is 49, but how does that help you ?

Answer 3

(a+b)^2=a^2+b^2+2ab so  here a =1 , 2ab=14, we get that b=7

and it is (x+7)^2 = x^2+14x +49