Unit 1

Which formula represents the following arithmetic series?

6, 9, 12, 15, 18 . . .

• 6n+6

• 3n+5

• 3n+3

• 2n+4

What is the first term in the given arithmetic sequence? Type in the value only.

• 5, 2, -1, -4 . . .

• -3, 2, 7, 12 . . .

• 5, 8, 11, 14 . . .

• -3, -8, -13, -18 . . .

Which formula represents the explicit formula for the sequence?

20, 15, 10, 5 . . .

• a_n=-5n+25

• a_n=-5n+15

• a_n=a_n-1-5; a₁=20

• a_n=a_n-1+20; a₁=-5

What kind of sequence is the pattern 400, 200, 100, 50, 25, ...?

• Arithmetic
• Geometric
• Neither

Write an equation that models the following situation:

Samantha's hair was known to grow very rapidly. It began at a length of 6 in and grew at a rate of 14% a week.

(HINT: Write out the equation on a separate piece of paper and then simplify inside the parenthesis)

• y=6(0.14)^x

• y=6(1+14)^x

• y=6(1.14)^x

• y=6(0.86)^x

Write the next 3 terms of the geometric sequence:

5, 20, 80, 320, __, __, __, ...

Write the explicit formula for the geometric sequence:

100, 50, 25, 12.5, ...