How to solve it using explicit formula

Step-by-step explanation:

For these we always want to see how much each term is decreasing by, this will tell us what kind of series  it is.

-40, -47, -54, -61

Each time it DECREASES by -7, so it is an arithmetic sequence

The explicit form is found with two parts.  the start and how much each term changes by.  The start is -40 and the change is -7, so the explicit formula is -40 - 7(n-1).  This is assuming the first term is a_1.  If you are starting with a_0 instead you want to make (n-1) be n.  so if a_0 = -40 then you have -40 - 7n but if -40 = a_1 then you have -40 - 7(n-1)

the next one has a "common difference" of 30.  so now if -8 is a_0 you have -8 + 30n but if -8 is a_1 then you have -8 + 30(n-1)

points are handed out whenever you post answers.

brainliest answers are handed out by the person asking the question, so whether your answer is picked depends entirely on whether the asker bothers to pick

if you're asking about your rank, it depends on having a certain number of points and a certain number of brainliest answers. for example, at the time of this writing, i have 44338 points out of 15000 needed for the next (nearly triple the requirement! ) but i only have 24 out of 50 required brainliest answers. this number decays, meaning after a certain amount of time (i think about a month), the total number of brainliest answers you've earned doesn't count toward this total. (i've been stuck at the same rank for a long

the lesson to learn here is that you shouldn't worry about points or rank. chances are, no matter how good an answer you may provide, your efforts will go mostly unnoticed unless you focus on the newest/most active questions that get posted.

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step-by-step explanation: