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3 years ago

Plsss Help me plsssssssssssss

Mathematics

1 answer:

Mazyrski [523]3 years ago

5 0

Answer:

If, a = 2 and b = 3

It's not equivalent.

<h3>Diego</h3><h3> $4a + 9b = 7a + 5b - 3a + 4b \\ 4(2) + 9(3) = 7(2) + 5(3) - 3(2) + 4(3) \\ 8 + 27 = 14 + 15 - 6 + 12 \\ 35 = 35 \\$ </h3>

It's equivalent.

The correct equation is 4a + 9b.

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X+7y=24 and x-9y=-24 doing elimination

nirvana33 [79]

The easy thing to do is eliminate x by subtraction

x + 7y = 24
- x - 9y = -24
-------------------
16y = 48

now solve for y and then substitute the value into either original equation to find x

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4 years ago

A torus is formed by rotating a circle of radius r about a line in the plane of the circle that is a distance R (> r) from th

jeyben [28]

Consider a circle with radius $r$ centered at some point $(R+r,0)$ on the $x$ -axis. This circle has equation

$(x-(R+r))^2+y^2=r^2$

Revolve the region bounded by this circle across the $y$ -axis to get a torus. Using the shell method, the volume of the resulting torus is

$\displaystyle2\pi\int_R^{R+2r}2xy\,\mathrm dx$

where $2y=\sqrt{r^2-(x-(R+r))^2}-(-\sqrt{r^2-(x-(R+r))^2})=2\sqrt{r^2-(x-(R+r))^2}$ .

So the volume is

$\displaystyle4\pi\int_R^{R+2r}x\sqrt{r^2-(x-(R+r))^2}\,\mathrm dx$

Substitute

$x-(R+r)=r\sin t\implies\mathrm dx=r\cos t\,\mathrm dt$

and the integral becomes

$\displaystyle4\pi r^2\int_{-\pi/2}^{\pi/2}(R+r+r\sin t)\cos^2t\,\mathrm dt$

Notice that $\sin t\cos^2t$ is an odd function, so the integral over $\left[-\frac\pi2,\frac\pi2\right]$ is 0. This leaves us with

$\displaystyle4\pi r^2(R+r)\int_{-\pi/2}^{\pi/2}\cos^2t\,\mathrm dt$

Write

$\cos^2t=\dfrac{1+\cos(2t)}2$

so the volume is

$\displaystyle2\pi r^2(R+r)\int_{-\pi/2}^{\pi/2}(1+\cos(2t))\,\mathrm dt=\boxed{2\pi^2r^2(R+r)}$

6 0

3 years ago

PLEASE HELP IM BEHIND AND SCHOOL IS OUT IN 2 DAYS

Alexxx [7]

Answer: #1 his school is out

Step-by-step explanation: #2 bcuz all sides equal to 66cm.

Please mark me brainlest.✌✌

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3 years ago

Which expression can be used to convert 22 Australian dollars to US dollars?

Nadusha1986 [10]

$22 AUD * 1 USD / 1.2 AUD
Hope that helps

5 0

3 years ago

Read 2 more answers

if you have a rectangle with a length of 0.5 x + 10 feet and a width of 6 feet how could you find the area written in its simple

Greeley [361]

<h2>Greetings!</h2>

Answer:

x + 20 = area

Step-by-step explanation:

You need to recall the equation for a rectangle:

Width x Length = Area

So simply plug the values into this:

(0.5x+10) * 6

(0.5x * 6) + (10 * 6)

= 3x + 60

Simplified down by dividing by three:

$\frac{3x}{3} + \frac{60}{3}$ = area

<h3>x + 20 = area</h3>
<h2>Hope this helps!</h2>

3 0

3 years ago