Which are perfect square trinomials? select two options a. x^2 -9 b. x^2 -100 c. x^2 - 4x + 4 d. x^2 +10x +25 e. x^2 +15x + 36

C.

D.

Step-by-step explanation:

A trinomial is perfect square trinomial if,

,

A.

By comparing,

a = 1, b = 0, c = -9,

⇒ it is not a perfect square trinomial.

B.

By comparing,

a = 1, b = 0, c = -100,

⇒ it is not a perfect square trinomial.

C.

By comparing,

a = 1, b = -4, c = 4,

⇒ it is a perfect square trinomial.

D.

By comparing,

a = 1, b = 10, c = 25,

⇒ it is a perfect square trinomial.

E.  

By comparing,

a = 1, b = 15, c = 36,

⇒ it is not a perfect square trinomial.

people went from manufacturing one object at a time by hand to manufacturing many objects in factories

answer: 2 and 1

step-by-step explanation: got this question