20, 15, 10, 5, 0, -5, -10, -15, -20 and so on.
5
4,8,12,16,20
sequence 4 5 6 sum =10 sequecnce 0 5 10 sum=10
2
5, 11, 17, 23, 29
37
To find the first three terms of an arithmetic sequence with a common difference of -5, we first need the last term. If we denote the last term as ( L ), the terms can be expressed as ( L + 10 ), ( L + 5 ), and ( L ) for the first three terms, since each term is derived by adding the common difference (-5) to the previous term. Thus, the first three terms would be ( L + 10 ), ( L + 5 ), and ( L ).
5
it is 8.
4,8,12,16,20
sequence 4 5 6 sum =10 sequecnce 0 5 10 sum=10
2
To find the sum of the arithmetic sequence from 3 to 90 that is divisible by 5, we first identify the terms: the first term is 5 and the last term is 90. The sequence of terms divisible by 5 is 5, 10, 15, ..., 90. This is an arithmetic sequence where the first term (a = 5), the last term (l = 90), and the common difference (d = 5). The number of terms (n) can be calculated as ((l - a)/d + 1 = (90 - 5)/5 + 1 = 18). The sum (S_n) of the sequence can be calculated using the formula (S_n = n/2 \times (a + l)), resulting in (S_{18} = 18/2 \times (5 + 90) = 9 \times 95 = 855). Thus, the sum is 855.
5, 11, 17, 23, 29
a1=2 d=3 an=a1+(n-1)d i.e. 2,5,8,11,14,17....
Double it every time and so the next number will be 80
They are 14, 42, 126, 378 and 1134.