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Students in Mrs. Doyle's classes use 3/4 of a bottle of hand sanitizer every week. Which expression can be used to find how many

vampirchik [111]

Answer:

A. 12 x 3/4

Step-by-step explanation:

7 0

2 years ago

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Which calculation should be used to calculate s9 for the arithmetic sequence an=3n-1

Ganezh [65]

Answer: Choice A

S9 = (9/2)*(2+26)

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The formula is

Sn = (n/2)*(a1+an)

where

Sn = sum of the first n terms (nth partial sum)

n = number of terms

a1 = first term

an = nth term

In this case,

n = 9

a1 = 2 (plug in n = 1 into the formula an = 3n-1 and simplify)

an = a9 = 26 (plug n = 9 into the formula an = 3n-1 and simplify)

So,

Sn = (n/2)*(a1+an)

S9 = (9/2)*(2+26)

will help us find the sum of the first 9 terms of this arithmetic sequence

7 0

3 years ago

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The graph of y = |2 is shifted to the left by 6 units.<br> What is the equation of the new graph?

Tasya [4]

Answer:

From your question, I am assuming you are talking about an absolute value graph. In this case the answer would be y = |2 + 6|

Step-by-step explanation: Always remember, when you are graphing absolute value graphs:

When you shift left or right, you put the amount you are shifting inside the absolute value sign.

When you are shifting up or down, you put the amount you are shifting outside the absolute value sign.

When shifting left on a graph, you usually think of subtraction. However, when dealing with absolute value graphs, when you are shifting left, you use addition, as you can see in this problem.

The same goes for right. You use subtraction when shifting right, contrary to what you may think.

However, when you go up, you still use addition, and when you shift down, you still use subtraction.

3 0

3 years ago

What is the answer to " What do electrons wear on their feet"?

LekaFEV [45]

Electrons do not have FEET

4 0

3 years ago

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There are 8 tennis players in a round robin tournament, which means each team will play every other team once. How many matches

Aliun [14]

<h3>Answer: 28</h3>

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Explanation:

Method 1

Imagine a table with 8 rows and 8 columns to represent all possible match-ups. You can actually draw out this table or just think of it as a thought experiment.

There are 8*8 = 64 entries in the table. Along the northwest diagonal, we have each team pair up with itself. This is of course silly and impossible. We cross off this entire diagonal so we drop to 64-8 = 56 entries.

Then notice that the lower left corner is a mirror copy of the upper right corner. A match-up like AB is the same as BA. So we must divide by 2 to get 56/2 = 28 different matches.

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Method 2

There are 8 selections for the first slot, and 8-1 = 7 selections for the second slot. We have 8*7 = 56 permutations and 56/2 = 28 combinations.

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Method 3

Use the nCr combination formula with n = 8 and r = 2

$n C r = \frac{n!}{r!(n-r)!}\\\\8 C 2 = \frac{8!}{2!*(8-2)!}\\\\8 C 2 = \frac{8!}{2!*6!}\\\\8 C 2 = \frac{8*7*6!}{2!*6!}\\\\ 8 C 2 = \frac{8*7}{2!}\\\\ 8 C 2 = \frac{8*7}{2*1}\\\\ 8 C 2 = \frac{56}{2}\\\\ 8 C 2 = 28\\\\$

There are 28 combinations possible. Order doesn't matter (eg: match-up AB is the same as match-up BA).

Notice how the (8*7)/2 expression is part of the steps shown above in the nCr formula.

7 0

1 year ago