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Olegator [25]
3 years ago
9

PLEASE HELP!!!what is the explicit formula for the sequence7 2 -3 -8 -13

Mathematics
2 answers:
Mariulka [41]3 years ago
7 0

Assuming the index start from 1, i.e. the first element is a_1, the answer is the last one: a_n = -5n+12


In fact, the elements of the sequence differ by 5 units from each other, and are descending, which justify the -5n part.


Nevertheless, the sequence starts from 7, so when n=1 we must have


-5+k=7 \iff k=12


hence the formula


a_n = -5n+12

Goryan [66]3 years ago
5 0
It is D.

When you plug in the step number instead of "n" you need to get "a" for your answer.
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Ina a class of 30 children,60% can swim. how many children cannot swim?
rewona [7]
60% of the total (30) can swim
60% of 30 = (60/100)*30 = 0.60*30 = 18
So 18 children can swim

This means 30-18 = 12 cannot swim

---------------------------------------------------------

An alternative is to do it this way: 

We know 60% can swim so that means 40% cannot swim. 
Notice how 100% - 60% = 40%
Or in other words, the 60% and 40% add to 100%. This is because we have two choices: either the person can swim or cannot swim

Since 40% cannot swim, this means
40% of 30 = (40/100)*30 = 0.40*30 = 12
and we get the same result as before

---------------------------------------------------------

Final Answer: 12
6 0
3 years ago
Algebra 2 unit 5 please help
Digiron [165]
You know the formula of discriminant

a  b
c  d
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7 0
3 years ago
What are the coefficients for the binomial expansion of (a + b)^3?
sashaice [31]

Answer:

Required coefficient :coefficient of 1st, 2nd, 3rd and 4th term are 1, 3,3,1 respectively.

Explanation:  

Formula for binomial expansion is (a+b)^n=^nC_0\cdot a^n\cdot b^0+^nC_1\cdota^(n-1)\cdot b^1+------b^n

We will substitute the values a=a, b=b and n=3  in the formula for binomial expansion we will get

^3C_0\cdot a^3\cdot b^0+^3C_1\cdot a^2\cdot b^1+^3C_2\cdot a^1\cdot b^2+^3C_3\cdot a^0\cdot b^3

After simplification of the terms we will get

a^3+3\cdot a^2\cdot b+3\cdot a\cdot b^2+b^3

Since, ^nC_r=\frac{n!}{(r!)(n-r)!}

Therefore the required coefficient : coefficients of 1st, 2nd, 3rd and 4th term are 1, 3,3,1 respectively.

5 0
2 years ago
Read 2 more answers
EXPERT HELP: DON'T GUESS AND EXPLAIN THE ANSWER
Doss [256]

Answer:

B

Step-by-step explanation:

8 0
2 years ago
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What is the equation of a line that passes through the point (2, 7) and is perpendicular to the line whose equation is y=x/4+5 ?
worty [1.4K]

Answer:

y = -4x+15

Step-by-step explanation:

y=x/4+5 may be presented as y = 1/4 x + 5, where a=1/4, b=5

swapping numerator and denominator and inserting an opposite sign in a=1/4, we have:

1/4 --------> 4/1 -------> -4/1 = -4

y = -4x+n

Point (2,7) means that x=2, y=7 substitute it to the equation y=-4x+n, calculate "n":

7=-4*2+n ------>    7=-8+n ------->   7+8 = n -------> 15=n

substituting n=15 to the equation y=-4x+n, we get finally y=-4x+15


8 0
3 years ago
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