Answer:
13
Step-by-step explanation:
where n is the number of terms, a1 is the first term and an is the last term. The sum of the first n terms of an arithmetic sequence is called an arithmetic series . Example 1: Find the sum of the first 20 terms of the arithmetic series if a1=5 and a20=62 .An arithmetic sequence is a sequence where the difference between any two consecutive terms is a constant. ... As with any recursive formula, the initial term of the sequence must be given. An explicit formula for an arithmetic sequence with common difference d is given by an=a1+d(n−1) a n = a 1 + d ( n − 1 ) .
Answer:
Mikhail is 42 years old
Step-by-step explanation:
Answer:
The answer is no solution.
Step-by-step explanation: First, you would add + 12 to both sides of the equation so that you would have 5c + 21 = 5c. Then, you would subtract 5c from both sides of the equation. This would leave you with 21 = 0. Since this is not true, the equation would have no solution.