SOLUTION: I cannot find the solution to -5, 10, -15, 20, ....

Question 110183This question is from textbook Algebra II Tennessee Edition
: I cannot find the solution to -5, 10, -15, 20, .... This question is from textbook Algebra II Tennessee Edition

Found 2 solutions by solver91311, scott8148:
Answer by solver91311(24713) (Show Source): You can put this solution on YOUR website!
First notice that the sign on each term alternates and the odd numbered terms are negative. That means a good place to start is to have each term contain the factor , which yields a positive 1 for all even n, and a negative 1 for all odd n.
:
The next thing to notice is that the absolute value of each element increases by 5 each subsequent element, so 5n is a good expression for that.
:
Putting it all together you get:
:

:
Check:

:
And the 5th term should be:

:
Exercise for the student: What would you do if your series had the odd terms positive and the even terms negative, i.e. the exact opposite of the problem given?

Answer by scott8148(6628) (Show Source): You can put this solution on YOUR website!
(-1)^n will give the changing signs ... 5n will give the numbers
so 5n(-1)^n
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