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What value of c makes x2 + 6x + c a perfect square trinomial?

2 Answers

5 votes

Answer:

c=9

Explanation:


x^2+6x+c

The given polynomial is a perfect square trinomial.

using completing square method to find the perfect square.


\Rightarrow x^2+6x+c


a^2+2ab+b^2=(a+b)^2

Now we compare the given polynomial


a^2+2ab+b^2\rightarrow x^2+2\cdot 3\cdot x+c


a^2\rightarrow x^2


2ab\rightarrow 2\cdot 3\cdot x


b^2\rightarrow c

2ab=6x

b=3

But
b^2\rightarrow c

So, c=9

Hence, The value of c is 9 to make perfect square.

User Zong
by
4.8k points
5 votes
c = 9

x² + 6x + 9
= (x+3)(x+3)
= (x + 3)²

it is a perfect square trinomial when c is equal to 9


Follow my account. (:
User Mohamed Ramrami
by
5.0k points