Answer: 
Step-by-step explanation:
The triangle CDE is shown in the image attached.
The formula for calculate the distance between two points is:

Then, we can calculate the lenght of each side of the triangle:

Therefore, the perimeter is:

A is the correct letter name for D1 i believe
Let the n-th term be called

We see that if we choose

then the other numbers follow the pattern

(see :

)
Hence the sequence will be
Answer: 1) Value is placed on top of the X =90
2) Value is placed on the bottom of the X =21
3) Factored form will be (3x+5)(3x+2)
Step-by-step explanation:
Since we have given that

As we know the quadratic form :

1) Value is placed on top of the X is given by

2) Value is placed on the bottom of the X is given by

3) Factorised form:
We will use "Split the middle term":

Hence, Factored form will be
(3x+5)(3x+2)
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