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3 votes
Which polynomial is a perfect square trinomial?

36x2 − 18x − 9
4a2 − 28a − 49
25b2 − 40b + 16
4x2 − 6x + 9

User Jameshales
by
8.1k points

2 Answers

6 votes
25b^2 -40b +16 = (5b -4)^2

so this is the right answer sure
User Maame
by
8.0k points
3 votes

Answer:

Option 3rd is correct


25b^2-40b+16

Explanation:

Formula for perfect square trinomial is given by:


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

From the given options:

A polynomial which is a perfect square trinomial is,
25b^2-40b+16

Since,

We can write this as:


25b^2-40b+16 = (5b)^2-2 \cdot (5b) \cdot 4+4^2

Apply the formula we have;


25b^2-40b+16 = (5b-4)^2

Therefore,
25b^2-40b+16 is a perfect square trinomial

User Erick Ramirez
by
9.0k points
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