Find the value of c that make x^2-7x+c a perfect square trinomial

[Hancko]

Hello Tutors, I Please request assistance with the following:

I am stuck with the solution of -7/2, but apparently, that is the incorrect answer. What is the concept that I need to understand here?

 

[Dr.Peterson]

Hello Tutors, I Please request assistance with the following:
View attachment 25311
I am stuck with the solution of -7/2, but apparently, that is the incorrect answer. What is the concept that I need to understand here?

The trinomial will be (x - 7/2)^2; but that doesn't mean c is -7/2! What do you get when you expand this trinomial?

 

[Hancko]

The trinomial will be (x - 7/2)^2; but that doesn't mean c is -7/2! What do you get when you expand this trinomial?

I do not understand how to expand this trinomial, I thought of the concept of factorization?

 

[Deleted member 4993]

I do not understand how to expand this trinomial, I thought of the concept of factorization?

Do you know:

(a - b)² = a² + b² - 2*a*b

 

[Dr.Peterson]

I do not understand how to expand this trinomial, I thought of the concept of factorization?

How did you get -7/2?

What we're doing here is sort of un-expanding, so knowing how to expand is a prerequisite.

But it's not the trinomial we are expanding; what I meant to say was, "What do you get when you expand this binomial squared to a trinomial?"