SOLUTION: Hi, I'm having a really tough time with these two questions. Any help is greatly appreciated, thank you! 1. For the sequence 15,12,9,... find the common difference and the nth t

Question 438685: Hi, I'm having a really tough time with these two questions. Any help is greatly appreciated, thank you!
1. For the sequence 15,12,9,... find the common difference and the nth term.
2. If 3x-1, 2x+2 and 2x-1 are in Arithmetic Progression, find value of x.

Answer by richard1234(7193) (Show Source): You can put this solution on YOUR website!
1. Common difference is 3. Assuming we start with the first term denoted , we can write (after some practice you'll be able to instantly find an expression for the nth term, then simply change n to n-1 or n+1 to satisfy the sequence).

2. If they are in arithmetic progression, then

.
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