Question Which of the following is equivalent to -14-8x0,5+0.75? O -9.25 -10.25 -17.25 -18.75

9514 1404 393

  -1

Step-by-step explanation:

We notice that we want term a1 and have terms a17 and a33. These terms (every 16-th term) form an arithmetic sequence. The middle term (a17) is the average of the other two, so we have ...

  a17 = (a1 +a33)/2

  2a17 -a33 = a1 = 2(10) -21 = -1

  a1 = -1

Additional comment

You could go to the trouble to find the general term of the sequence.

  an = a1 +d(n -1)

  a17 = a1 + d(17 -1) = 10

  a33 = a1 + d(33 -1) = 21

Subtracting the first equation from the second, we have ...

  16d1 = 11

  d1 = 11/16

Using the first equation, we find ...

  a1 +(11/16)(17 -1) = 10

  a1 = 10 -11 = -1 . . . . same as above.