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3 years ago

Math Practices and Problem Solving

Mathematics

1 answer:

spin [16.1K]3 years ago

8 0

The store sold 482 cameras in the month of March.

An equation is an expression that shows the relationship between two or more variables and numbers.

Assuming that the same number of camera is sold each month. Let x represent the amount of camera sold in March.

Since the electronics store sold 1,446 cameras in the first 3 months, hence:

3x = 1446

x = 482 cameras

The store sold 482 cameras in the month of March.

Find out more on equation at: brainly.com/question/2972832

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Using 0-9 only once to figure this out... HELP please

NeX [460]

I have no idea on D. Sorry. I hope this helps. They may not be right I didn’t quite understand the directions.

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3 years ago

A rock thrown vertically upward from the surface of the moon at a velocity of 36m/sec reaches a height of s = 36t - 0.8 t^2 met

Verdich [7]

Answer:

a. The rock's velocity is $v(t)=36-1.6t \:{(m/s)}$ and the acceleration is $a(t)=-1.6 \:{(m/s^2)}$

b. It takes 22.5 seconds to reach the highest point.

c. The rock goes up to 405 m.

d. It reach half its maximum height when time is 6.59 s or 38.41 s.

e. The rock is aloft for 45 seconds.

Step-by-step explanation:

Velocity is defined as the rate of change of position or the rate of displacement. $v(t)=\frac{ds}{dt}$
Acceleration is defined as the rate of change of velocity. $a(t)=\frac{dv}{dt}$

The rock's velocity is the derivative of the height function $s(t) = 36t - 0.8 t^2$

$v(t)=\frac{d}{dt}(36t - 0.8 t^2) \\\\\mathrm{Apply\:the\:Sum/Difference\:Rule}:\quad \left(f\pm g\right)'=f\:'\pm g'\\\\v(t)=\frac{d}{dt}\left(36t\right)-\frac{d}{dt}\left(0.8t^2\right)\\\\v(t)=36-1.6t$

The rock's acceleration is the derivative of the velocity function $v(t)=36-1.6t$

$a(t)=\frac{d}{dt}(36-1.6t)\\\\a(t)=-1.6$

b. The rock will reach its highest point when the velocity becomes zero.

$v(t)=36-1.6t=0\\36\cdot \:10-1.6t\cdot \:10=0\cdot \:10\\360-16t=0\\360-16t-360=0-360\\-16t=-360\\t=\frac{45}{2}=22.5$

It takes 22.5 seconds to reach the highest point.

c. The rock reach its highest point when t = 22.5 s

Thus

$s(22.5) = 36(22.5) - 0.8 (22.5)^2\\s(22.5) =405$

So the rock goes up to 405 m.

d. The maximum height is 405 m. So the half of its maximum height = $\frac{405}{2} =202.5 \:m$

To find the time it reach half its maximum height, we need to solve

$36t - 0.8 t^2=202.5\\36t\cdot \:10-0.8t^2\cdot \:10=202.5\cdot \:10\\360t-8t^2=2025\\360t-8t^2-2025=2025-2025\\-8t^2+360t-2025=0$

For a quadratic equation of the form $ax^2+bx+c=0$ the solutions are

$x_{1,\:2}=\frac{-b\pm \sqrt{b^2-4ac}}{2a}$

$\mathrm{For\:}\quad a=-8,\:b=360,\:c=-2025:\\\\t=\frac{-360+\sqrt{360^2-4\left(-8\right)\left(-2025\right)}}{2\left(-8\right)}=\frac{45\left(2-\sqrt{2}\right)}{4}\approx 6.59\\\\t=\frac{-360-\sqrt{360^2-4\left(-8\right)\left(-2025\right)}}{2\left(-8\right)}=\frac{45\left(2+\sqrt{2}\right)}{4}\approx 38.41$

It reach half its maximum height when time is 6.59 s or 38.41 s.

e. It is aloft until s(t) = 0 again

$36t - 0.8 t^2=0\\\\\mathrm{Factor\:}36t-0.8t^2\rightarrow -t\left(0.8t-36\right)\\\\\mathrm{The\:solutions\:to\:the\:quadratic\:equation\:are:}\\\\t=0,\:t=45$

The rock is aloft for 45 seconds.

5 0

4 years ago

Select the correct choices to complete the sentence. Three drivers competed in the same fifteen drag races. The mean and standar

sweet [91]

Answer:

<h2> Driver B has the fastest race time</h2>

Step-by-step explanation:

From the options presented, driver B has the fastest typical race time because he recorded the smallest time taken to complete an individual race.

Also from the standard deviation given (3.96) for driver B, it shows that the individual time spread from the standard deviation is minimal and that the driver maintained a fairly consistent time of race throughout the racing period.

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3 years ago

Given that <img src="https://tex.z-dn.net/?f=z%3Dx%2Biy" id="TexFormula1" title="z=x+iy" alt="z=x+iy" align="absmiddle" class="l

Mnenie [13.5K]

Answer:

$z= 5-2i$

Step-by-step explanation:

Start replacing!

$(x+iy) + 4i (x-iy) = -3+18i \\ x+iy +4ix -4i^2 y = -3 + 18i \\\\x + i (4x+y) +4y = -3 + 18i\\x+4y + (4x+y) i = -3 + 18i$

Now two complex numbers are equal if both the real and imaginary parts are equal, which gives you the system of equation $\left \{x+4y=-3} \atop {4x+y=18} \right.$

Pick any method to solve it and you'll get $x=5, y= -2$

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3 years ago

8/3+7/5a<br><br> Simplify your answer as much as possible.

Rainbow [258]

Answer:

mixed number: 4 1/15

Exact: 61/15

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3 years ago

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