What is the formula for 1, -3, 9, -27?
arithmetic or geometric?

The formula of the geometric sequence is a =

Step-by-step explanation:

The terms of the sequence are 1, -3, 9, -27

∵ -3 ÷ 1 = -3

∵ 9 ÷ -3 = -3

∵ -27 ÷ 9 = -3

∴ There is a common ratio between each two consecutive terms

∴ The sequence is geometric

∵ The formula of the geometric sequence is a = a , where

∵ The first term is 1

∴ a = 1

∵ The common ratio is -3

∴ r = -3

→ Substitute them in the formula above

∵ a = (1)

∴ a =

∴ The formula of the geometric sequence is a =

answer: the price of one pound cabbage = $ 0.8

the point (10,8) represents that the cost of 10 pounds cabbage is $ 8

step-by-step explanation:

since, here is a proportional relation between the number of pounds of cabbage (x) and the price in dollars (y).

therefore, we can write,

⇒ y = k x

where k is the constant of proportionality.

now, point (5,4) is in the line.

thus, it will satisfies the above equation of line.

⇒ 4 = 5 k

⇒ k = 0.8

thus, the equation of the line is,

y = 0.8 x

a) for x = 1,

y = 0.8

therefore, the cost of one pound of cabbage is 0.8 dollars.

b) in the below graph (10,8) represents that the cost of 10 pounds of cabbage is 8 dollars.

other answer is correct. i had used the radius of the radius somehow. a website: