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2 votes
Which polynomial is a perfect square trinomial?

A. 49x^2 − 28x + 16

B. 4a^2 − 20a + 25

C. 25b^2 − 20b − 16

D. 16x^2 − 24x − 9

User Can
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1 Answer

1 vote
B
Recall that (a+b)²=a²+2ab+b², and (a-b)²=a²-2ab+b²
4a²=(2a)²
25=5²
20a=2*(2a)*5
the square is (2a-5)²
User Pavel K
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