Question

What number should be added to the expression x^2 + 6x to change it into a perfect square trinomial?

A.
3

B.
6

C.
9

D.
12

Answer 1

ax^2 + bx +c

complete the square:
(you only have a and b)
b divided by 2 quantity squared.
Do you understnad what your b value is?

Answer 2

Usually we say x^2 to mean x squared to keep from getting confused. A perfect square would be (x+c)^2 which is (x+c)(x+c) using the FOIL method we get
x^2+2cx+c^2
What would c be in your equation? Would that mean you would have to add c^2 to the equation to get the perfect square?

Answer 3

c= (b/2)^2

Answer 4

b is the constant on your second term...

Answer 5

So its B?

Answer 6

No

Answer 7

what is half of the x term? 6/3
Now what is the square of that number?

Answer 8

sorry 6/2

Answer 9

A! ok thnx @plainntall

Answer 10

Actually it is c

You have x^2+6x
They want you to add a number to make the perfect square. If you add 9 you have
x^2+6x+9
which is (x+3)(x+3) or (x+3)^2

You found it by taking have of the x coefficient which was 6 to get 3 and then squared 3 to get 9.

Answer 11

Oh ok thnx