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Evgesh-ka [11]
3 years ago
9

Find the sum of the first 18 terms of the arithmetic sequence whose nth term is an = 3n - 1.

Mathematics
1 answer:
vodka [1.7K]3 years ago
7 0

Answer:

495

Step-by-step explanation:

In order to find the sum of the first 18 terms you have to find the 18th term and the first term using the equation given.

a1=3(1)-1        a1=2

a18=3(18)-1   a18= 53

Then plug in 53 for an, 18 for n, and 2 in for a1 in the sum equation: Sn=n/2(a1+an)  

Sn=18/2(2+53)  Solve for sn= 495

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Write an equation with a slope of -1/2 in each form.<br> point-slope form<br> slope-intercept form.
Evgen [1.6K]

For the case of a line through

(

2

,

7

)

and

(

1

,

−

4

)

we have

slope

m

=

Δ

y

Δ

x

=

−

4

−

7

1

−

2

=

−

11

−

1

=

11

Using the point

(

2

,

7

)

we can write the equation of the line in point slope form as:

y

−

7

=

m

(

x

−

2

)

where the slope

m

=

11

.

That is:

y

−

7

=

11

(

x

−

2

)

To get point intercept form, first expand the right hand side so...

y

−

7

=

11

x

−

(

11

⋅

2

)

=

11

x

−

22

Then add

7

to both sides to get:

y

=

11

x

−

15

=

11

x

+

(

−

15

)

This is point intercept (

y

=

m

x

+

c

) form with slope

m

=

11

and intercept

c

=

−

15

.

6 0
3 years ago
− 4n = -1 3− 4n - 18
Lady_Fox [76]

Answer:

0=-31

Step-by-step explanation:

7 0
3 years ago
Multiply 1/3 1/5<br><br>-1/10<br><br>-1/15<br><br>1/15<br><br>1/10​
defon

Answer:

1/337500

(Decimal: 0.000003)

Step-by-step explanation:

8 0
4 years ago
Julio tenía 2/3 de una tablilla de chocolate en el recreo comió 1/5 que fracción de la tablilla le queda?
Furkat [3]

Answer:

7/15 de la tablilla de chocolate le va a quedar.

Step-by-step explanation:

2/3 se converte en 10/15

y 1/5 se converte en 3/15

Entonces le va a quedar 10/15-3/15 = 7/15 de la tablilla de chocolate.

5 0
3 years ago
Read 2 more answers
If a positive integer that is not a multiple of 5 is divided by 5, what is the least possible remainder
solniwko [45]
I would say 1 would be the least possible remainder...

11/5 = 2 remainder 1
21/5 = 4 remainder 1
31/5 = 3 remainder 1

and since ur dealing with positive integers (whole numbers), 1 is gonna be the smallest
8 0
4 years ago
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