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vagabundo [1.1K]
3 years ago
7

Help finding the sum

Mathematics
1 answer:
Mamont248 [21]3 years ago
5 0
It is asking you to find the sum of k^2 - 1 from k=1 to k=4. Since that is only 4 numbers, calculating the sum by hand wouldn’t be that bad.

(1^2 - 1) + (2^2 - 1) + (3^2 - 1) + (4^2 - 1) = 26

The easier way to find the sum is to use a few simple formulas.

When we have a term that is just a constant c, the formula is c*n.

When we have a variable k, the formula is k*n*(n+1)/2.

When we have a squared variable, the formula is k*n*(n+1)*(2n+1)/6.

In this case, we have a squared variable k^2 and a constant of -1.

So plug in n=4 to the formulas:

4*5*9/6 - 1*4 = 26

The answer is 26







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The first term in a sequence is 84. The pattern follows the rule add 24. What are the next four terms?
weqwewe [10]

Answer: 108, 132, 156, and 180

Step-by-step explanation:

If you need to add 24 to the first term for the next 4 terms, you would have

84 + 24 = 108

108 + 24 = 132

132 + 24 = 156

156 + 24 = 180

So your sequence would be 108, 132, 156, and 180 for the next 4 terms.

5 0
2 years ago
Solve for x<br> -12 = 4(x – 5)<br> X =
bonufazy [111]

Answer:

-12=4x-20

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3 years ago
7b + 15 +4 it says write two equivalent expressions.Help
VARVARA [1.3K]

Answer:

1. 4b+3b+15+4

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Step-by-step explanation:

Both are equivalent expressions :))

7 0
2 years ago
Can someone explain how this is right please
Daniel [21]
Because when you add them all up that's what the answers are
4 0
3 years ago
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zalisa [80]

Answer:

129.5 Square feet is the correct answer.

Step-by-step explanation:

I am a 100% SURE of that.

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7 0
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