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3 years ago

Evaluate 3xy²-y³ for x=-1 and y=2.help.

Mathematics

2 answers:

yanalaym [24]3 years ago

7 0

The answer to this problem is -20

Annette [7]3 years ago

7 0

Step-by-step explanation:

=3xy²-y³

=3(-1)(2)²-(2)³

=3(-1)(4)-(8)

= -12-8

= -20

hope it helps.

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The time between arrivals of customers at the drive-up window of a bank follows an exponential probability distribution with a m

castortr0y [4]

Answer:

a) 50.34% probability that the arrival time between customers will be 7 minutes or less.

b) 24.42% probability that the arrival time between customers will be between 3 and 7 minutes

Step-by-step explanation:

Exponential distribution:

The exponential probability distribution, with mean m, is described by the following equation:

$f(x) = \mu e^{-\mu x}$

In which $\mu = \frac{1}{m}$ is the decay parameter.

The probability that x is lower or equal to a is given by:

$P(X \leq x) = \int\limits^a_0 {f(x)} \, dx$

Which has the following solution:

$P(X \leq x) = 1 - e^{-\mu x}$

The probability of finding a value higher than x is:

$P(X > x) = 1 - P(X \leq x) = 1 - (1 - e^{-\mu x}) = e^{-\mu x}$

Mean of 10 minutes:

This means that $m = 10, \mu = \frac{1}{10} = 0.1$

A. What is the probability that the arrival time between customers will be 7 minutes or less?

$P(X \leq x) = 1 - e^{-\mu x}$

$P(X \leq 7) = 1 - e^{-0.1*7} = 0.5034$

50.34% probability that the arrival time between customers will be 7 minutes or less.

B. What is the probability that the arrival time between customers will be between 3 and 7 minutes?

$P(3 \leq X \leq 7) = P(X \leq 7) - P(X \leq 3)$

$P(X \leq x) = 1 - e^{-\mu x}$

$P(X \leq 7) = 1 - e^{-0.1*7} = 0.5034$

$P(X \leq 3) = 1 - e^{-0.1*3} = 0.2592$

$P(3 \leq X \leq 7) = P(X \leq 7) - P(X \leq 3) = 0.5034 - 0.2592 = 0.2442$

24.42% probability that the arrival time between customers will be between 3 and 7 minutes

3 0

3 years ago

The terms in the sequence decrease by the same amount each time:

luda_lava [24]

Answer:the nth term of the sequence, Tn= -3n +12

Step-by-step explanation:

The nth term of an arithmetic progression is given as

Tn= a+ (n-1) d

where a= first term

and d = common difference

In this sequence, 9, 6 ,3 ,0, -3, -6 we can see that the number is decreasing by 3

The first term, a= 9

and common difference, d = -3

using our formulae

Tn= a+ (n-1) d

Tn= 9 + ( n-1) -3

Tn=9- 3n+ 3

Tn= -3n +12

7 0

3 years ago

Solve the following equation:<br> 9n² - n - 2/3 = 0

KIM [24]

Answer:

see explanation

Step-by-step explanation:

Given

9n² - n - $\frac{2}{3}$ = 0 ← multiply through by 3 to clear the fraction

27n² - 3n - 2 = 0 ← factoring

Consider the factors of the product of the n² term and the constant term which sum to give the coefficient of the n- term

product = 27 × - 2 = - 54 and sum = - 3

The factors are - 9 and + 6

Use these factors to split the n- term

27n² - 9n + 6n - 2 = 0 ( factor the first/second and third/fourth terms )

9n(3n - 1) + 2(3n - 1) = 0 ← factor out (3n - 1) from each term

(3n - 1)(9n + 2) = 0

Equate each factor to zero and solve for n

3n - 1 = 0 ⇒ 3n = 1 ⇒ n = $\frac{1}{3}$

9n + 2 = 0 ⇒ 9n = - 2 ⇒ n = - $\frac{2}{9}$

3 0

3 years ago

Marcel said he can find 52 times 10 by adding a 0 to the end of 52 to get 520

Rainbow [258]

Answer:

No he can not because if you add 0 to 52 you get 520 and the answer has to be 520

Step-by-step explanation:

4 0

3 years ago

Determine the answer to 3 + -5 and explain the steps using a number line

Marizza181 [45]

Adding a positive to a negative, you would look at the number with the greater absolute value, and that number would determine the sign of the sum.

5 - 3 = 2

Since 5 is bigger, you use that sign

-5

-2

Answer: -2

6 0

3 years ago

Read 2 more answers

Evaluate 3xy²-y³ for x=-1 and y=2.help.​

Evaluate 3xy²-y³ for x=-1 and y=2.help.