Find a formula for the nth term in this arithmetic sequence:
a1 = -7, 22 = -1, a3 = 5, 24 = 11, ...

Step-by-step explanation:

Arithmetic Sequences

The arithmetic sequences can be identified because each term is obtained by adding or subtracting a fixed number to the previous term. That number is called the common difference.

The equation to calculate the nth term of an arithmetic sequence is:

Here a1 is the first term and r is the common difference.

The given sequence is:

We can find the common difference by subtracting successive terms:

Since all the differences are equal, r=6. Thus, the general term is:

Operating:

The nth term is:

it costs $20 to interview each person for a survey. find the cost to obtain a +- 3% margin of error.

step-by-step explanation:

copy and paste, put it in google

hello from mrbilldoesmath!

answer:

(7 x + 6 y) (49 x^2 - 42 x y + 36 y^2)

discussion:

the trick is to recognize that 343 = 7^3 and 216 = 6^3 and, in general,

a^3 + b^3 =   (a + b) (a^2 - a b + b^2).

in our case

343x^3+216y^3   =   (7x)^3 + (6y)^3

so take a = 7x and b = 6y in the above equation to get the answer.

you,

mrb