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3 years ago

Find the sum of the first 21 terms of the sequence 5, 9, 13, 17, 21, ... a. 945 c. 947 b. 944 d. 946

2 answers:

6 0

See how the arithmetic sequence is made:
5, 5+4=9, 9+4=13, 13+4=17, ...
So the 21th term will be:
5( first term)+20( n-1 term)•4= 85
And the sum of the first 21 is :
21(5+85)/2= 21•45= 945

DIA [1.3K]3 years ago

4 0

Answer:A 945 is correct

Step-by-step explanation:

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3 years ago

Assume that the growth rate of a population of ants is proportional to the size of the population at each instant of time. Suppo

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ln(A) = C*t + C1 where C1 is another constant that comes out of integration and t is time in days.
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3 years ago

What is the area of the triangular flag below?

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Answer:

Here is your answer

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2 years ago

Determine the ratio in which the point (–6, m) divides the join of A(–3, –1) and B(–8, 9). Also, find the value of m.

PSYCHO15rus [73]

Answer:

Ratio = 3 : 2 and value of m = 5.

Step-by-step explanation:

We are given the end points ( -3,-1 ) and ( -8,9 ) of a line and a point P = ( -6,m ) divides this line in a particular ratio.

Let us assume that it cuts the line in k : 1 ratio.

Then, the co-ordinates of P = $( \frac{-8k-3}{k+1},\frac{9k-1}{k+1} )$ .

But, $\frac{-8k-3}{k+1}$ = -6

i.e. -8k-3 = -6k-6

i.e. -2k = -3

i.e. $k = \frac{3}{2}$

So, the ratio is k : 1 i.e $\frac{3}{2} : 1$ i.e. 3 : 2.

Hence, the ratio in which P divides the line is 3 : 2.

Also, $\frac{9k-1}{k+1}$ = m where $k = \frac{3}{2}$

i.e. m = $\frac{\frac{9 \times 3}{2}-1}{\frac{3}{2}-1}$

i.e. m = $\frac{27-2}{3+2}$

i.e. m = $\frac{25}{5}$

i.e. m = 5.

Hence, the value of m is 5.

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2 years ago

Read 2 more answers

the number of members in a club dropped from 80 to 52. what is the percent of decrease in the number of members

Illusion [34]

Percent of decrease :
Original - New / Original
so...
80 - 52 / 80 ---->
28/80
.35 multiply by 100 to get percent
35% increase Hope I helped if you have any questions let me know! :)

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2 years ago