Find S10 for -1 + -7 + -13 + -19

1 answer:

4 0

First we find the common difference...to do this we subtract the first term from the second term. -7 - (-1) = -7 + 1 = -6

now we are going to find the 10th term
an = a1 + (n-1)*d <== formula for finding any term in arithmetic series
a1 = 1st term, d = common difference, n = term we want to find
now we sub
a10 = -1 + (10 -1) * -6
a10 = -1 + (9 * -6)
a10 = -1 - 54
a10 = - 55

now we will find the sum
Sn = (n (a1+ an)) / 2 <== formula for finding the sum
S10 = (10(-1 - 55))/2
S10 = (10(-56) / 2
S10 = -560/2
S10 = - 280

so the sum of the first 10 numbers is -280

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PART TWO MATH TEST :)<br><br> Please Help! I will give brainliest and donuts <33

ra1l [238]

Hey there,

Question #1

The answer would be in the attachment below.
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Question #2

The answer would be in the attachment below.
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Question #3

The answer would be in the attachment below.
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Question 4#

The last one was kind of tricky. But, as I saw this attachment, I noticed on how the rectangle was actually 3/4 on the base and for the height, it was 1/2. So by doing this,we need to find the area, and we would multiply these both. 1/2 x 3/4 = 3/8 but by looking at your options, those are not simplified so . . .your answer would be 6/16 because 3x2=6 & 8x2=16.
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I really hope this can help you Amanda.

Have a great day! =)

~Jurgen