Problem: algebra 2 need help. sequences and series.
What is the rule for the nth term of the arithmetic sequence that has the two given terms.
11.) a12=0, a19=28
12.) d=-5, a10=-60
For the series marked 11, a change of seven positions shows a change in value of 28.
28/7 = 4, indicating that each position increases by 4. Position a12 is zero, so
going backwards 12 steps would reduce the value by -4 * 12 = -48 at a0. In order
for a12 to be 0, the equation must be 4x - 48, with x being the sequence number.
a[x] = 4x - 48
For the series marked 12, the d seems to be out of place. Perhaps it should be a, and
probably a0. Going on that assumption (bad policy), the 10 steps from a0 to a10 cause
the value to change by -60 - (-5) = -55. This is a change of -5.5 per step.
a[x] = -5.5x - 5