Question

NEED HELP..... Select the polynomial that is a perfect square trinomial. 36x^2 − 4x + 16 16x^2 − 8x + 36 25x^2 + 9x + 4 4x^2 + 20x + 25

Answer 1

Answer: Choice D.  4x^2 + 20x + 25

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Explanation:

Perfect square trinomials are in the form (a+b)^2 = a^2+2ab+b^2

So the first and last terms must be perfect squares. The middle term is twice that of the square roots of each first and last term.

Choice D fits the description because 4x^2 = (2x)^2 is the first term, so a = 2x and 25 = 5^2 is the last term meaning b = 5. Note how 2ab = 2*2x*5 = 20x is the middle term.

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

(2x+5)^2 = (2x)^2+2*2x*5+5^2

(2x+5)^2 = 4x^2 + 20x + 25

Answer 2

Answer:

(2x+5)² or (2x+5)(2x+5)

Step-by-step explanation:

4x²+ 20x + 25

(2x       ) (2x      )     first step 2x*2x=4x²

(2x  +  5   )(2x  +   5  )  the constant sign is plus so it can be ( minus × minus=plus OR plus×plus=plus) look at the middle value it is positive so the two signs are positive or plus sign.

(2x+5)²