Which of the following constants can be added to x^2+15x to form a perfect square trinomial?
a. 15/2
b. 225/4
c. 15

Answer b.

Step-by-step explanation:

In order to get a perfect square trinomial from a binomial of the form: . the term to add should be the square of half of the coeficcient "b". That is: . Such will give you a trinomial that comes from the perfect square of the binomial:

In your case, b=15 therefore

Option C. The constant is

Solution:

Let us assume that the constant is c.

Now to the equation will be -------- (i)

We know the square formula  

As per the formula we can write the equation as,

Now if we need make the equation perfect square,

Then as per the formula c should be

And the equation will be the perfect square as

So, the constant is