Question

Determine which polynomial is a perfect square trinomial.

49x^2 - 28x + 16

9a^2 - 30a + 25

25b^2 - 45b - 81

16x^2 - 24x - 9

Answer 1

@SolomonZelman @mlb004

Answer 2

for a perfect square you have

\[(a + b)^2 = a^2 + 2ab + b^2\]

or

\[(a-b)^2 = a^2 - 2ab + b^2\]

so looking at the 2 general cases above you can eliminate the last 2 choices as
they have the last terms as negatives...

so for the 1st and 2nd which has a middle term that is double the product

Answer 3

Which one do you think it is ?

Answer 4

I would lean towards a

Answer 5

I would not -:(

Answer 6

B is more reliable.

Answer 7

Thanks!