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3 years ago

Solve the system by using the combination method 4x+9y=7 4x-9y=9

1 answer:

7 0

The two original functions are 4x+9y=7 and 4x-9y=9
To use the combination method, add all the values of the two equations together to cancel out one of the variables
4x+4x+9y-9y=7+9
8x=16
8x/8=16/8
x=2
4(2)+9y=7
8+9y=7
8-8+9y=7-8
9y=-1
y=- $\frac{1}{9}$

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3 years ago

An orange has 20 fewer calories

Andreyy89

Answer:

90 calories in a banana.

Step-by-step explanation:

O = B - 20 where O is the number calories in an orange and B is a that in banana.

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3 years ago

Suppose the null hypothesis, H0, is: Darrell has enough money in his bank account to purchase a new television. What is the Type

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<h2>Answer with explanation:</h2>

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3 years ago

Marylou buys a package of 500 jewels to decorate 4 different pairs of jeans. She uses the same number of jewels on each pair of

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500 divided by 4 = 125 so
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3 years ago

An insurance company sells automobile liability and collision insurance. Let X denote the percentage of liability policies that

qaws [65]

Answer:

-764.28

Step-by-step explanation:

Given the joint cumulative distribution of X and Y as

$F(x,y) = \frac{xy(x+y)}{2000000}\ \ \ \, \ 0\leq x100, 0\leq y\leq 100$

#First find $F_x$ and probability distribution function , $f_x(x)$ :

$F_x(x)=F(x,100)\\\\\\=\frac{100x(x+100)}{2000000}\\\\\\\\=\frac{100x^2+10000x}{2000000}\\\\\\=>f_x(x)=\frac{x}{10000}+\frac{1}{200}$

#Have determined the probability distribution unction , $f_x(x)$ , we calculate the Expectation of the random variable X:

$E(X)=\int\limits^{100}_0 \frac{x^2}{10000}+\frac{x}{200} dx \\\\\\\\=|\frac{x^3}{30000}+\frac{x^2}{400}|\limits^{100}_0\\\\=58.33\\\\$

#We then calculate $E(X^2)$ :

$E(X^2)=\int\limits^{100}_0 \frac{x^3}{10000}+\frac{x^2}{200}\ dx\\\\=\frac{x^4}{40000}+\frac{x^3}{600}|\limits^{100}_0=4166.67\\\\Var(X)=E(X^2)-(E(X))^2=4166.67-58.33^2\\\\Var(X)=764.28$

Hence, the Var(X) is 764.28

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3 years ago