Find C to complete the square: X2 + 6X + C

Answer 1

Whenever you have an expression of the form

x² + bx + c,

you complete the square by setting

c = b² / 4

In this problem,

b = 6.

You should be able to finish from here.

Answer 2

You want to put this in the form (x+b)^2 + c

To do this take half of the coefficient of b from the ordinal form which is 6/2=3 as use this as your new b

This give you (x+3)^2.

If you foil this out you get x^2 +6x +9 so you have added 9 to the original expression so now all you need to do is subtract 9 to keep things balanced

The final expression then is (x+3)^2 -9

So c= -9