Me, i'm lost.
astronomers classify stars according to their brightness by assigning them a stellar “magnitude.” the higher the magnitude the dimmer the star. the dimmest stars visible to the naked eye have stellar magnitudes of 6. the table below shows the relative brightness of different stellar magnitudes.

a. y = 250 (0.4)^x

b. 0.066

Step-by-step explanation:

The equation can be modeled as a geometric sequence, where the first term is 100 and the common ratio is 0.4.

y = 100 (0.4)^(x − 1)

This can also be simplified to:

y = 250 (0.4)^x

When x = 9:

y = 250 (0.4)^9

y = 0.066

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take good notes.

do your homework.

use mnemonics and other tricks.

do practice tests.

note: the best i know.