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ikadub [295]
2 years ago
9

Find the following sums ( for letter C)

Mathematics
1 answer:
anygoal [31]2 years ago
6 0

Each number in the sum is even, so we can remove a factor of 2.

2 + 4 + 6 + 8 + ... + 78 + 80 = 2 (1 + 2 + 3 + 4 + ... + 39 + 40)

Use whatever technique you used in (a) and (b) to compute the sum

1 + 2 + 3 + 4 + ... + 39 + 40

With Gauss's method, for instance, we have

S = 1 + 2 + 3 + ... + 38 + 39 + 40

S = 40 + 39 + 38 + ... + 3 + 2 + 1

2S = (1 + 40) + (2 + 39) + ... + (39 + 2) + (40 + 1) = 40×41

S = 20×21 = 420

Then the sum you want is 2×420 = 840.

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In the given figure p=120° and y : z=2 : 3 Find x, y and z​
Sindrei [870]

Answer:

x = 60°

y = 72°

z = 48°

Step-by-step explanation:

x = 180 - p = 180 - 120 = 60

Since y;z = 3:2 ,   2y = 3z  or z = 2y/3

Now, x + y + z = 180

60 + y + 2y/3 = 180     Multiply thru by 3 to remove the fraction

180 + 3y + 2y = 540

180 + 5y = 540

5y = 360

y = 72

z = 2(72)/3 = 48

Check:  60 + 72 + 48 = 180

5 0
3 years ago
4x + 7 = 23slove this
Juli2301 [7.4K]

Given:

4x + 7 = 23

Let's solve for x.

First Step:

Subtract 7 from both sides

4x + 7 - 7 = 23 - 7

4x = 16

Next Step:

DIvide both sides by 4

\begin{gathered} \frac{4x}{4}=\frac{16}{4} \\  \\ x\text{ = 4} \end{gathered}

ANSWER:

x = 4

4 0
1 year ago
Use the substitution method
vitfil [10]

Answer:

z = 9

z = 2

z = 5

z = 8

z = 11

Step-by-step explanation:

5 0
3 years ago
What's the answer to this please help. :)
Alexxandr [17]
I think the answer is 32 if I did my math right sorry if it wrong
6 0
3 years ago
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A multiplication table. In the row labeled 3, the numbers 9, 12, 15, and 18 are highlighted. Consider the highlighted products.
Basile [38]
3, 3x3=9, 3x4=12, 3x5=15, 3x6=18
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3 years ago
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