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3 years ago

What is the sum of the first 30 odd numbers? How to calculate it without having to add all of them.

1 answer:

4 0

See that odd number are in a Aritmetic progression with a1 = 1 and r = 2

30th number of sequence is given by:

$a_{30}=a_1+29r\\
\\
a_{30}=1+29*2\\
\\
a_{30}=59$

Now you can calculate the sun by:

$S_{30}=\frac{30(1+59)}{2}=\frac{30*60}{2}=900$

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3 years ago

Marcus wants to use a model to determine the difference

grigory [225]

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We want to see how we can model the difference: -8 - 3 + 3

The correct option is D:

"add 3 positive counters and 3 negative counters"

We know that Marcus starts with 8 negative counters, corresponding to the first term in our difference.

Now, let's study the math of our expression.

-8 - 3 + 3

Remember that we can perform the operation in any order we want, so we can write this as:

-8 + (-3 + 3)

Notice that the thing inside the parentheses is equal to zero, so we have:

- 8 + (-3 + 3) = -8

So to not change the value, we add 3 and we subtract 3.

Now if we have 8 negative counters, and we want to add 3 positive counters and not change the value, then we also need to add 3 negative counters to "cancel" the 3 positive counters we added.

Then the correct option is D.

To learn more about Marcus refer to,

brainly.com/question/23140234

#SPJ1

8 0

1 year ago

Does anyone know the answer

arsen [322]

Answer:

i cant see the photos

Step-by-step explanation:

sorry talaga

6 0

3 years ago

Read 2 more answers

Find the distance between the two points in simplest radical form.<br> (-1,9) and (4, -3)

jolli1 [7]

Answer:

GIVEN BY POINTS :-

( -1, 9) , ( 4 , -3)

Here ,

$\bullet \: \: x _{1} = - 1 \\ \bullet \: \: x _{2} = 4 \\ \bullet \: \: y _{1} = 9 \\ \bullet \: \: y _{2} = - 3 \\$

Using Distance formula :

$= > \sf d = \sqrt{( {x _{2} - x _{1}) }^{2} + {( {y _{2} - y _{1}) }^{2} } } \\ \\ = > \sf d = \sqrt{ ({ 4 + 1)}^{2} + { ( - 3 - 9)}^{2} } \\ \\ = > \sf d = \sqrt{ {5}^{2} + {( - 12)}^{2} } \\ \\ = > \sf d = \sqrt{25 + 144} \\ \\ = > \sf d = \sqrt{169} \\ \\ = > \boxed{ \sf{ d = 13\:units }}\\$

8 0

3 years ago