Question

Which polynomial is a perfect square trinomial?

49x2 − 28x + 16

4a2 − 20a + 25

25b2 − 20b − 16

16x2 − 24x − 9

Answer 1

pls explain

Answer 2

The one with this form: $$a^2 +2ab+b^2$$

Answer 3

?

Answer 4

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

Answer 5

?

Answer 6

Let's look at the first choice: $$49x^2 − 28x + 16 =(7x)^2 -2*14x+4^2$$ Does that fit the "perfect square" pattern?

Answer 7

no?

Answer 8

Ok, can you check the others?

Answer 9

i guess i can try

Answer 10

i dont really get how to

Answer 11

Write each one in this form first$$4a^2 − 20a + 25=(2a)^2-2*10a+5^2$$

Answer 12

i still dint get it

Answer 13

Perfect squares look like this $$a^2+2ab+b^2=(a+b)^2$$ $$a^2-2ab+b^2=(a-b)^2$$

Answer 14

what happenned to the 2

Answer 15

So the first two do not fit the pattern, right?

Answer 16

yes

Answer 17

What do you mean "what happenned to the 2" ???

Answer 18

in 2ab whear did it go

Answer 19

Where "in 2ab"?

Answer 20

Here is the 3rd one: $$ 25b^2 − 20b − 16=(5b)^2-2*10b-4^2$$ does it fi the pattern?