Check all polynomials that are perfect square trinomials:

49x2 − 8x + 16

4a2 − 20a + 25

25b2 − 5b + 10

16x2 − 8x + 1

im not sure...need help !

Question

Check all polynomials that are perfect square trinomials: 

 49x2 − 8x + 16 

 4a2 − 20a + 25 

 25b2 − 5b + 10 

 16x2 − 8x + 1 

im not sure...need help !

anonymous · Answer

How can they trinomial?? they are with the highest power of 2...

anonymous · Answer

IDK that why i need help...

anonymous · Answer

The first term has to be a perfect square, the last term has to be a perfect square, and the middle term has to be twice the product of the first and last terms

jim_thompson5910 · Answer

You mean "and the middle term has to be twice the product of the SQUARE ROOT of the first and last terms"

anonymous · Answer

Thats what i meant

anonymous · Answer

2. 4 is a perfect square, 25 is a perfect square, but 20 is not twice the product of 25 so it would not be a perfect square trinomial
3. 25 is a perfect square but the other is not
4. 16 is a perfect square but the other not
So that leaves 1. which is a perfect square trinomial 
1. 49 is a perfect square, 16 is a perfect square which is 4, 4*2=8 so this is the only perfect square trinomial