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3 years ago

7

Ryan can dig a 10 ft by 10ft hole in five hours. Jim can dig the same hole in six hours. How long would it take them if they wor

ked together?

1 answer:

Slav-nsk [51]3 years ago

4 0

Three hours is the answer

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Solve for the roots in the equation below. In your final answer, include each of the necessary steps and calculations. Hint: Use

QveST [7]

$\bf 27\implies 3^3\\\\
i^3\implies i\cdot i\cdot i\implies i^2\cdot i\implies -1\cdot i\implies -i\\\\
-----------------------------\\\\
x^3-27i=0\implies x^3+3^3(-i)=0\implies x^3+(3^3i^3)=0
\\\\\\
x^3+(3i)^3=0\\\\
-----------------------------\\\\
\textit{difference of cubes}
\\ \quad \\
a^3+b^3 = (a+b)(a^2-ab+b^2)\qquad
(a+b)(a^2-ab+b^2)= a^3+b^3\\\\
-----------------------------\\\\$

$\bf (x+3i)[x^2-3ix+(3i)^2]=0\implies 
\begin{cases}
x+3i=0\implies \boxed{x=-3i}\\\\
x^2-3ix+(3i)^2=0
\end{cases}
\\\\\\
\textit{now, for the second one, we'd need the quadratic formula}
\\\\\\
x^2-3ix+(3i)^2=0\implies x^2-3ix+(3^2i^2)=0
$

$\bf x^2-3ix+(-9)=0\implies x^2-3ix-9=0
\\\\\\
\textit{quadratic formula}\\\\
x= \cfrac{ - {{ b}} \pm \sqrt { {{ b}}^2 -4{{ a}}{{ c}}}}{2{{ a}}}\implies x=\cfrac{3i\pm\sqrt{(-3i)^2-4(1)(-9)}}{2(1)}
\\\\\\
x=\cfrac{3i\pm\sqrt{(-3)^2i^2+36}}{2}\implies x=\cfrac{3i\pm\sqrt{-9+36}}{2}
\\\\\\
x=\cfrac{3i\pm\sqrt{27}}{2}\implies \boxed{x=\cfrac{3i\pm 3\sqrt{3}}{2}}$

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3 years ago

Find x 20 and 15 geometric mean

Colt1911 [192]

Answer: 17.320508075689

Step-by-step explanation:

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2 years ago

A weather station in Antarctica reports that the temperature is currently -44 °C and has been rising at a constant rate of 4.5 °

-Dominant- [34]

Answer:

-17

Step-by-step explanation:

4.5*6=27

so -44++27

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3 years ago

The number of apples in 15 pound boxes sold at a farm is normally distributed as shown below.

Nataly_w [17]

Answer: 16%

Step-by-step explanation:

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3 years ago

A store sells a package of 7 water bottles for $5.60.<br> What is the price per water bottle?

Luden [163]

Since there is 7 water bottles in a package and the total price is 5.60, you divide 7 by 5.60 which gives you 1.25 per bottle

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3 years ago