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4 years ago

Solve -2(2x+5) -3(x-1)

Mathematics

1 answer:

OLEGan [10]4 years ago

8 0

<h2>Hello!</h2>

The answer is:

$-2(2x+5)-3(x-1)=-7x-7\\$

To solve the problem, we need to perform the operations and then, add like terms.

We need to apply the distributive property, which is defined by the following way:

$a(b+c)=ab+ac$

Also, we need to remember how to add like terms. Like terms are terms that share the same exponent and the same variable, for example:

$3x+5x+x^{2}=8x+x^{2}$

We were able to add only the first two terms since they are like terms, both are sharing the same exponent and the same variable.

So, we are given the expression:

$-2(2x+5)-3(x-1)$

Then, solving we have:

$-2(2x+5)-3(x-1)=-4x-10-(3x-3)\\\\-4x-10-(3x-3)=-4x-10-3x+3\\\\-4x-10-3x+3=-4x-3x-10+3\\\\-4x-3x-10+3=-7x-7$

Hence, we have that the answer is:

$-2(2x+5)-3(x-1)=-7x-7\\$

Have a nice day!

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if on a scale drawing 35 feet are represented by 25 inches, then a scale of 1/8 inch represents how many feet?

kirill115 [55]

Answer:

7/40 feet

Step-by-step explanation:

Solve using proportions:

$\frac{25in}{35ft} =\frac{1/8 in}{?ft}$

Find the scale factor by dividing the numerators 25 by 1/8.

25 ÷ 1/8 = 200 This is the common ratio

To get from the top left number to the top right number, you divide 25 by 200.

To get from the bottom left number to the bottom right number, you divide 35 by 200.

35 ÷ 200 = 0.175

1/8 of an inch represents 0.175 feet.

To find 0.175 in fraction form, reduce 35/200 to its lowest terms.

35/200 = 7/40

1/8 of an inch represents 7/40 feet.

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4 years ago

Please help me with this question

zubka84 [21]

Answer: c. f - 3 + 6d

Explanation: 5d - d + 4 + 2d - 5f - 6f - 7
- 5f - 6f = f
4 - 7 = -3
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3 years ago

What is expression is equivalent to 5(9 t)

iris [78.8K]

Here you have: (45t)

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3 years ago

The equations 2x+7=3 and bx-10=-2 have the same solution for x. Find the value of b.

White raven [17]

Solve both equations for x:

2x+7 = 3

2x = -4

x = -2

Plug x into the equation which contains b:

b(-2) -10 = -2

-2b = 8

b = -4

Answer:

b = -4

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4 years ago

In Sweden, 10 people are struck by lightning every year, on average. Answer thefollowing questions about a given year in Sweden

emmainna [20.7K]

Answer:

a) 19.85% probability that a total of two people are struck by lightning during first four months of the year.

b) 22.68% probability that the year has 5 good and 7 bad months

Step-by-step explanation:

We are going to use the Poisson distribution and the binomial distribition to solve this question.

Poisson distribution:

In a Poisson distribution, the probability that X represents the number of successes of a random variable is given by the following formula:

$P(X = x) = \frac{e^{-\mu}*\mu^{x}}{(x)!}$

In which

x is the number of sucesses

e = 2.71828 is the Euler number

$\mu$ is the mean in the given time interval.

Binomial distribution:

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

In which $C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by the following formula.

$C_{n,x} = \frac{n!}{x!(n-x)!}$

And p is the probability of X happening.

a.Find the probability that a total of two people are struck by lightning during first four months of the year.

10 people during a year(12 months).

In 4 months, the mean is $\mu = \frac{10*4}{12} = 3.33$

This is P(X = 2).

$P(X = x) = \frac{e^{-\mu}*\mu^{x}}{(x)!}$

$P(X = 2) = \frac{e^{-3.33}*(3.33)^{2}}{(2)!} = 0.1985$

19.85% probability that a total of two people are struck by lightning during first four months of the year.

b.Say that a month is good is no one is struck by lightning, and bad otherwise. Find the probability that the year has 5 good and 7 bad months.

Probability that a month is good.

P(X = 0), Poisson

The mean is $\mu = \frac{10*1}{12} = 0.8333$

$P(X = x) = \frac{e^{-\mu}*\mu^{x}}{(x)!}$

$P(X = 0) = \frac{e^{-0.8333}*(0.8333)^{0}}{(0)!} = 0.4346$

Find the probability that the year has 5 good and 7 bad months.

Now we use the binomial distribution, we want P(X = 5) when n = 12, p = 0.4346. So

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 5) = C_{12,5}.(0.4346)^{5}.(0.5654)^{7} = 0.2268$

22.68% probability that the year has 5 good and 7 bad months

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3 years ago