Find the sum of the sequence: 108, 105, 102,...,15

1968

Step-by-step explanation:

The given sequence is a finite arithmetic sequence.

Step 1: Determine the number of terms in the sequence

For an arithmetic sequence, the nth term:

A(n)=a+(n-1)d

In the sequence:

Therefore, to find which term the number 15 is, we have:

15=108+(n-1)(-3)

15=108-3n+3

15=111-3n

3n=111-15

3n=96

Number of terms in the sequence, n=32

Step 2: Find the sum of the sequence

For an arithmetic sequence with a given first and last term:

  21.3

step-by-step explanation:

multiplying the given equation by c/sin(25°), we get

  c = 9/sin(25°) ≈ 21.2958 ≈ 21.3

we assume "c" is the length of ab, the side opposite angle c in triangle abc.

the answer is d

step-by-step explanation:

y+3=-4(x-2)

y+3=-4x+8

  -3         -3  

y=-4x+5