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3 years ago

R^2+8r=-7solve the equation with the quadratic formula showing work

Mathematics

1 answer:

Yuliya22 [10]3 years ago

7 0

Answer:

Step-by-step explanation:

r²+8r=−7

Step 1: Subtract -7 from both sides.

r²+8r−(−7)=−7−(−7)

r²+8r+7=0

Step 2: Use quadratic formula with a=1, b=8, c=7.

r= $r=\frac{-b+or-\sqrt{-4ac} }{2a}$

$r=\frac{-8+or-\sqrt{(8})^2-4(1)(7) }{2(1)}$

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Here are the prices for cans of juice that are the same brand and the same size at different stores. Which store offers the best

lubasha [3.4K]

The best deal is offered by the Store Z

<em><u>Solution:</u></em>

We have to find which store offers the best deal

This is found by calculating the unit rate of each store

Unit rate of each store means price per can .i.e price of 1 can

<h3><u>Store X: 4 cans for $2.48</u></h3>

Therefore, store X sells 4 cans for $ 2.48

Price of 1 can is found by dividing 2.48 by 4

$\text{Price of 1 can } = \frac{2.48}{4} = 0.62$

Thus unit rate of store X is $ 0.62 per can

<h3><u>Store Y: 5 cans for $3.00</u></h3>

Therefore, store Y sells 5 cans for $ 3.00

Price of 1 can is found by dividing 3.00 by 5

$\text{Price of 1 can } = \frac{3}{5} = 0.6$

Thus unit rate of store Y is $ 0.6 per can

<h3><u>Store Z: 59 cents per can</u></h3>

1 cents is equal to 0.01 dollar.

59 cents = 0.59 dollar

Thus unit rate of store Z is $ 0.59 per can

Comparing unit rate of store X, Y, Z

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3 years ago

Geometry problem in the picture: find the missing side and round to the nearest tenth

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Answer:

X= 19.9

Step-by-step explanation:

SOH CAH TOA

x is hypotenuse

Opposite is 15

Opposite & hypotenuse - sin

Sin(49) = o/h

Sin(49) = 15/h

Sin(49) x h = 15

÷Sin(49)

h = 15 ÷ Sin(49)

h=19.8751949

Hope this helps!

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2 years ago

Assume that there is a 8% rate of disk drive failure in a year. a. If all your computer data is stored on a hard disk drive wit

romanna [79]

Answer:

0.9936 = 99.36% probability that during a year, you can avoid catastrophe with at least one working drive

Step-by-step explanation:

For each disk, there are only two possible outcomes. Either it works, or it does not. The probability of a disk working is independent of any other disk, which means that the binomial probability distribution is used to solve this question.

Binomial probability 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.

Assume that there is a 8% rate of disk drive failure in a year.

So 100 - 8 = 92% probability of working, which means that $p = 0.92$

Two disks are used:

This means that $n = 2$

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This is:

$P(X \geq 1) = 1 - P(X = 0)$

In which

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$P(X = 0) = C_{2,0}.(0.92)^{0}.(0.08)^{2} = 0.0064$

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0.9936 = 99.36% probability that during a year, you can avoid catastrophe with at least one working drive

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Answer:

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Step-by-step explanation:

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