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

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.

(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

(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

x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18

true

step-by-step explanation: