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2 years ago

8

Evaluate the summation of 2 n plus 5, from n equals 1 to 12..

1 answer:

kirza4 [7]2 years ago

4 0

<span>Let f(n) = 2n + 5. Then we must simply calculate (f1), f(2), ..., (f12). And we have that f(1) = 2*1 + 5 <=> f(1) = 7; f(2) = 2*2 + 5 <=> f(2) = 9; f(3) = 2*3 + 5 <=> f(3) = 11. And so on. It's easy to see that the rest of the results will be 13, 15, 17, 19, 21 and so on. So the summation will be S = 7 + 9 + 11 +... + 29 <=> S = 216</span>

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Five less than two times a number is sixty-nine. A. 5 – 2t = 69 t = –32 B. 2t – 5 = 69 t = 37 C. 5 + 2t = 69 t = 32 D. none of t

Julli [10]

Let's translate the expression step by step:

"Five less than..." $\to$ we will have to subtract five from something

"two times a number" $\to 2t$ .

So, we have

"Five less than two times a number" $\to 2t-5$ .

This "is sixty-nine", where "is" means "is equal to". So, the equation is

$2t-5=69$

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2 years ago

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egoroff_w [7]

Answer:

(3) $x = 7.5$ and $y = 51$

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Step-by-step explanation:

Question 3

Required

Solve for x and y

We have:

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Collect like terms

$16x + 10x = 180 + 18 - 3$

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Solve for x

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$x = 7.5$

Also:

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So, we have:

$16 * 7.5 - 18 = 2y$

$120 - 18 = 2y$

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Divide by 2

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Question 4:

Required

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Collect like terms

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marshall27 [118]

Answer:

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Step-by-step explanation:

C is the central angle here (the one in between)

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Answer:

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Step-by-step explanation:

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Answer:

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Step-by-step explanation:

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