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3 years ago

Evaluate the exponential expression. 3•42

Mathematics

1 answer:

LuckyWell [14K]3 years ago

8 0

Answer:

Step-by-step explanation:

Trust me

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If copies of all your computer data are stored on four independent hard disk drives, what is the probability that during a yea

Natasha2012 [34]

Answer:

$P(Atleast\ 1) = 0.9999992$

Step-by-step explanation:

Given

$p = 3\%$ --- rate of hard disk drives failure

$n = 4$ --- number of hard disk drives

See comment for complete question

Required

$P(Atleast\ 1)$

First, calculate the probability that the none of the 4 selected is working;

$P(none) = p^4$

$P(none) = (3\%)^4$

$P(none) = (0.03)^4$

Using the complement rule, the probability that at least 1 is working is:

$P(Atleast\ 1) = 1 - P(none)$

This gives:

$P(Atleast\ 1) = 1 - 0.03^4$

$P(Atleast\ 1) = 0.9999992$

5 0

2 years ago

Which expression is irrational?

Mrrafil [7]

Answer:

$\sqrt{50}$

Step-by-step explanation:

An irrational number is a number that isn't a whole number (integer).

$\sqrt{50}$ = 7.07

$\sqrt{1}$ = 1

$\sqrt{25$ = 5

$\sqrt{9}$ = 3

The first one is the only one that isn't an integer. So it is the answer.

8 0

3 years ago

Read 2 more answers

The area of a rectangular wall of a barn is 42 ft. Its length is 8 feet longer. Than twice its width. Find the length and width

stiv31 [10]

It is 42ft and 16 width

6 0

3 years ago

Read 2 more answers

Find the slope of a line that passes through points at (4,7) and (1,-1)

geniusboy [140]

To find the slope, use the equation slope=rise/run.
rise= 7-(-1) = 8
run = 4-1 = 3
The slope is 8/3

5 0

3 years ago

Help i dont understand how to complete this

Luda [366]

Answer: Josh = 19.8 hours, Danny = 10.8 hours

Step-by-step explanation:

$Josh: \dfrac{1}{x+9}\\\\\\Danny: \dfrac{1}{x}\\\\\\Together: \dfrac{1}{7}\\\\\\Josh\quad + \quad Danny\quad =\quad Together\\\dfrac{1}{x+9}\quad +\qquad \dfrac{1}{x}\qquad = \qquad \dfrac{1}{7}\\\\\\\underline{\text{Clear the denominator by multiplying by the LCM: (x+9)(x)(7)}}\\\\7(x) + 7(x+9)=x(x+9)\\7x + 7x + 63 = x^2+9x\\14x+63=x^2+9x\\0=x^2-5x-63\\\\\\\underline{\text{Use the quadratic formula to solve for x: }}x=\dfrac{-b\pm \sqrt{b^2-4ac}}{2a}$

$x=\dfrac{-(-5)\pm \sqrt{(-5)^2-4(1)(-63)}}{2(1)}\\\\\\.\quad =\dfrac{5\pm\sqrt{25+252}}{2}\\\\\\.\quad =\dfrac{5\pm\sqrt{277}}{2}\\\\\\.\quad =\dfrac{5\pm 16.6}{2}\\\\\\x =\dfrac{5+16.6}{2}\qquad x=\dfrac{5-16.6}{2}\\\\\\x=\dfrac{21.6}{2}\qquad \qquad x=\dfrac{-11.6}{2}\\\\\\x=10.8 \qquad \qquad x=-5.8$

Since time cannot be negative, x=-5.8 is an extraneous solution (not valid) so x = 10.8

Josh: x + 9 --> 10.8 + 9 = 19.8

Danny: x --> 10.8

****************************************************************************************

2a) k = 9.45 & 0.55

2b) x = 3/2

2c) x = 2/3 (x = -1 is an extraneous solution so is not valid)

2d) No Solution (x = 1 is an extraneous solution so is not valid)

Here is the work for 2a. Follow this format for b, c, & d

$\dfrac{3}{k^2-8x+12}=\dfrac{k}{k-2}-\dfrac{4}{k-6}\\\\\text{Since the denominator cannot equal zero, then } k \neq2\ and\ k\neq6\\\text{If either of the solutions are 2 or 6, then that solution needs to be crossed out}\\\\\underline{\text{Clear the denominator by multiplying by the LCM: (k-2)(k-6)}}\\\\3 = k(k-6)-4(k-2)\\3=k^2-6k-4k+8\\0=k^2-10k+5\\\\\\\underline{\text{Use the quadratic formula to solve for k}}$

$x=\dfrac{-(-10)\pm \sqrt{(-10)^2-4(1)(5)}}{2(1)}\\\\\\.\quad =\dfrac{10\pm\sqrt{100-20}}{2}\\\\\\.\quad =\dfrac{10\pm\sqrt{80}}{2}\\\\\\.\quad =\dfrac{10\pm8.9}{2}\\\\\\x=\dfrac{10+8.9}{2}\qquad x=\dfrac{10-8.9}{2}\\\\\\x=\dfrac{18.9}{2}\qquad x=\dfrac{1.1}{2}\\\\\\x=9.45\qquad x=0.55\\\\\\\text{Both answers are valid!}$

8 0

3 years ago