Question

What value for c will make the expression a perfect square trinomial? x2 – 7x + c

Answer 1

I assume the first part of that equation is x^2. -7/2= 3.5 ; 3.5^2=12.25 sooo it should end up as x^2-7x + 12.25. but I might be wrong.

Answer 2

Answer: 12.25

Explanation:

A perfect square trinomial is written as
`ax^2+2abx+b^2` , where

first term
`ax` = square of first term of binomial

second term=2abx=twice the product of both terms of binomial.

and third term 'c'=square of last term of binomial

In the given polynomial ,
`x^2+7x+c`, a=1

and 2ab = 7

When we put value of a =1, we get

`2(1)b=7\\\Rightarrow\ b=(7)/(2)`

Hence, in place of the question mark makes the given polynomial a perfect square trinomial =
`b^2=((7)/(2)^2=12.25`