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2 years ago

When written in simplest form the expression 5(3x + 2)+2(x-7) is?

Mathematics

1 answer:

Sophie [7]2 years ago

6 0

Answer:

Option 1

Step-by-step explanation:

5(3x+2) + 2(x-7)

15x + 10 + 2x -14

15x + 2x + 10 - 14

17x - 4

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What is an equivalent expression for 3 x 9

Lorico [155]

9x3 is equivalent to 27

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3 years ago

A rate simplified so that it has a denominator of 1

Yakvenalex [24]

This is called a unit rate.

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3 years ago

[25 POINTS] A cylinder has a volume of 400π cm3. Find the dimensions that minimize its surface area.

miss Akunina [59]

Answer:

r = 5.848cm, h = 11.696cm

Step-by-step explanation:

Surface area: $SA=2\pi rh+2\pi r^2$

Volume: $V=\pi r^2h$

Therefore, the height of a cylinder given its volume would be $h=\frac{V}{\pi r^2}$ , thus:

$SA=2\pi r(\frac{V}{\pi r^2})+2\pi r^2\\\\SA=\frac{2V}{r}+2\pi r^2\\\\SA=\frac{2(400\pi)}{r}+2\pi r^2\\\\SA=\frac{800\pi}{r}+2\pi r^2$

We now find the derivative of the surface area of the cylinder with respect to its radius and set it equal to 0, solving for the radius:

$\frac{d(SA)}{dr}=-\frac{800\pi}{r^2}+4\pi r$

$0=-\frac{800}{r^2}+4\pi r$

$0=800\pi+4\pi r^3$

$-800\pi=4\pi r^3$

$-200=r^3$

$r\approx5.848$

If $0If [tex]r>5.848$ , then the surface area of the cylinder increases

Therefore, the surface area is minimized when the radius is $r=5.848cm$ , making the minimum height $h=\frac{V}{\pi r^2}=\frac{400\pi}{\pi(5.848)^2}\approx11.696cm$ .

In conclusion, the 2nd option is correct.

3 0

2 years ago

I need help I don't understand this

Lady_Fox [76]

<h3><u>Answer</u> :</h3>

It is clear from the diagram that,

ㄥ6 + ㄥ8 = 180

⇒ (2x - 5) + (x + 5) = 180

⇒ (2x + x) + (5 - 5) = 180

⇒ 3x + 0 = 180

⇒ x = 180/3

⇒ x = 60°

◈ From the geometry of figure,

ㄥ3 = ㄥ6

⇒ ㄥ6 = (2x - 5)

⇒ ㄥ6 = (2×60 - 5)

⇒ ㄥ6 = 120 - 5

⇒ <u>ㄥ6 = 115°</u>

4 0

3 years ago

A rectangle has an area of x square units. The rectangle is dilated to create a new rectangle with an area of 9x square units. D

Alika [10]

The reactangle has an area of x.

So that means two numbers multiplied to each other equal to x. We can just think of itwo numbers that when multiplied equal to x as a and b.

So that means the side lengths are <u />a and b. And ab = x (will be using this right next).

And it was multiplied by some scale factor that made the new area 9x. So if the scale factor is y, then:

$(y\times a)\times (y\times b)=9x$
$y^2ab=9x$
$y^2x=9x$
$y=3$

y can not equal to -3, because the length of a side of any polygon can never be negative.

So the dilation is 3.

And so if the dimension is 5 by 8.

Then the area is $5 \times 8=40$

And so then $x=40$

And then after the dilation, it would be $9x=9(40) = 360$

We could check it another way too. Since we said the scale factor is 3, then:

$( 5 \times 3) \times (8 \times 3) = 15 \times 24 = 360$

So basically 15 by 24 is the new dimensions :)

6 0

3 years ago