Answer:

Step-by-step explanation:
It's an arithmetic sequence.

The difference is constant.
The explicit formula of an arithmetic sequence:

Substitute:

<em>use distributive property</em>

The question didn't make sense, could you add more to it?
Answer:
see the attachment photo!
Answer:
if that statement is true, then DE=ST, and ST=4 so your answer should be <u>DE=4</u>
Explanation:
you can tell that they are even from looking at the first statement, it states <u>DE</u>F=<u>ST</u>U, emphasizing on the DE=ST part, it gives your the answer right there because ST=4