Answer:
Step-by-step explanation:
<u>Key skills needed: Explicit formula, Geometric sequence</u>
1) This is a geometric sequence, meaning a constant (like 6 or 3.5) is being multiplied to every term. First we need to find the constant.
This can be done by doing -42 ÷ 7 or 252 ÷ -42
-42 ÷ 7 equals -6.
252 ÷ -42 also equals -6.
2) This means that constant is -6.
3) The general form for an explicit formula of a geometric sequence is:
--> r means the constant (or common ratio) that is being multiplied.
--> means the first term
--> means the "nth" numbered term (so
is the 3rd term,
is the 10th term and so on).
--> is just the "n" in
minus 1.
4) We can use this formula to create an explicit formula for the geometric sequence in the problem.
--> (Since we got -6 as the constant/common ratio).
--> (Since 7 is the 1st term)
This means that our formula would be -->
<em>Hope you understood and have a nice day!! :D</em>