Question

–20, - 12,5, 22, . . . An= A50=

Answer 1

Answer:

an = 17n - 46

a50 = 804

Step-by-step explanation:

-29, -12, 5, 22, ...

Subtract each number from the next one.

-12 - (-29) = 17

5 - (-12) = 17

22 - 5 = 17

The common difference is 17. This is an arithmetic sequence which starts with -29, and in which each subsequent value is 17 more than the previous value.

a1 = -29

a2 = -29 + 17

a3 = -29 + 2(17)

a4 = -29 + 3(17)

Notice that for each term, you have -29 and something added to it. What you add to -29 is 17 multiplied by 1 less than the number of the term. For term 1, 1 less than 1 is 0. You add 0 * 17 to -29 and get -29. term 1 is -29. For term 2, 1 less than 2 is 1. You add 1 * 17 to -29 and get -12, etc.

For term n, 1 less than n is n - 1. Add (n - 1) * 17 to -29 to get term n.

an = -29 + 17(n - 1)

This formula can be simplified.

an = -29 + 17n - 17

an = -46 + 17n

an = 17n - 46

a50 = 17(50) - 46

a50 = 804