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3 years ago

If x2-y2 = 10 and x+y = 5, what is the value of x-y? 2-5?

Mathematics

1 answer:

netineya [11]3 years ago

8 0

Answer:

x-y=2

I don't get why they are asking you what is 2-5. That seems super basic compared to the other question it is with. Since 5-2=3, then 2-5 or -5+2=-3.

Step-by-step explanation:

We are going to use identity x^2-y^2=(x-y)(x+y)

x^2-y^2=10

(x-y)(x+y)=10

(x-y)(5)=10

Since (2)(5)=10, this implies x-y=2.

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If 90 percent of automobiles in Orange County have both headlights working, what is the probability that in a sample of eight au

Marta_Voda [28]

Answer:

$P(X \geq 7) = P(X=7) +P(X=8)$

And we can find the individual probabilities using the probability mass function

$P(X=7)=(8C7)(0.9)^7 (1-0.9)^{8-7}=0.3826$

$P(X=8)=(8C8)(0.9)^8 (1-0.9)^{8-8}=0.4305$

And replacing we got:

$P(X \geq 7) = P(X=7) +P(X=8)=0.3826 +0.4305=0.8131$

Step-by-step explanation:

Previous concepts

The binomial distribution is a "DISCRETE probability distribution that summarizes the probability that a value will take one of two independent values under a given set of parameters. The assumptions for the binomial distribution are that there is only one outcome for each trial, each trial has the same probability of success, and each trial is mutually exclusive, or independent of each other".

Solution to the problem

Let X the random variable of interest "number of automobiles with both headligths working", on this case we now that:

$X \sim Binom(n=8, p=0.9)$

The probability mass function for the Binomial distribution is given as:

$P(X)=(nCx)(p)^x (1-p)^{n-x}$

Where (nCx) means combinatory and it's given by this formula:

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

And for this case we want to find this probability:

$P(X \geq 7) = P(X=7) +P(X=8)$

And we can find the individual probabilities using the probability mass function

$P(X=7)=(8C7)(0.9)^7 (1-0.9)^{8-7}=0.3826$

$P(X=8)=(8C8)(0.9)^8 (1-0.9)^{8-8}=0.4305$

And replacing we got:

$P(X \geq 7) = P(X=7) +P(X=8)=0.3826 +0.4305=0.8131$

7 0

3 years ago

Read 2 more answers

5(2x+6)= -4( -5 - 2x)+3x <br> Solve for x

lisov135 [29]

Answer: x = -7/2

Step-by-step explanation:

10x+ 30 = 20 +8x+ 3

10x+ 30=23+8x

10x-8x = 23-30

2x=-7

( a helpful app to help with these type of problems is photomath)

8 0

3 years ago

2. Which algebraic expression represents the following phrase?

oksian1 [2.3K]

The algebraic expression which represents the square of the difference of s and 6 is (s - 6)²

Step-by-step explanation:

Let us represent some words by mathematics expressions

Square a number ⇒ x²
Square the sum of two numbers ⇒ (x + y)²
Sum of the squares of two numbers ⇒ x² + y²
Square of difference of two numbers (x - y)²
The difference of square two numbers x² - y²

∵ The expression is the square of the difference of s and 6

- That means find the difference between s and 6 at first,

then square the difference

∵ The difference of s and 6 = s - 6

- Square this difference means but the difference in a bracket

and then square the bracket

∴ The square of the difference = (s - 6)²

The algebraic expression which represents the square of the difference of s and 6 is (s - 6)²

Learn more:

You can learn more about the algebraic expressions in brainly.com/question/10771256

#LearnwithBrainly

3 0

3 years ago

Alyssa had 59 dollars to spend on 6 books. After buying them she had 11 dollars. How much did each book cost

Mrrafil [7]

Answer: $20
Sandy had 138 dollars to spend on 6 books. After buying them she had 18 dollars. How much did each book cost? 20 dollars.

5 0

3 years ago

Which one of the following is an irrational number?

kondaur [170]

Answer:

sqrt(10)

Step-by-step explanation:

Since the second number ends and does not continue it wouldn't be the second one, and since the third is able to be predicted it wouldn't be the thrid one either and since the fourth one is 7 and is a whole number the only answer choice possible would be the first one.

7 0

3 years ago