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2 years ago

First answer gets brainliest. And one hundo points

Mathematics

2 answers:

enyata [817]2 years ago

5 0

Answer:The one you already have marked,B.

Step-by-step explanation:

Eduardwww [97]2 years ago

5 0

Answer:

option C.

Step-by-step explanation:

option C is the correct answer.

Direct variation: y = kx .........where k is constant.

10 = k * -5

k = -2

Then check if all are linear and matches.

y = -2 * -4

y = 8 ...matches.

then

y = -2 * -3

y = 6 ........matches

then

y = -2 * -2

y = 4 ........matches

then

y = -2*-1

y = 2 ......matches as well. so direct variation.

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Help please!!!! ASAP WILL MARK BRAINLIST IF REALLY FAST

Setler79 [48]

Answer:

1. Product

2. Difference

3. Difference

Step-by-step explanation:

7 0

3 years ago

A piece of paper is to display ~128~ 128 space, 128, space square inches of text. If there are to be one-inch margins on both si

Grace [21]

Answer:

The dimensions of the smallest piece that can be used are: 10 by 20 and the area is 200 square inches

Step-by-step explanation:

We have that:

$Area = 128$

Let the dimension of the paper be x and y;

Such that:

$Length = x$

$Width = y$

So:

$Area = x * y$

Substitute 128 for Area

$128 = x * y$

Make x the subject

$x = \frac{128}{y}$

When 1 inch margin is at top and bottom

The length becomes:

$Length = x + 1 + 1$

$Length = x + 2$

When 2 inch margin is at both sides

The width becomes:

$Width = y + 2 + 2$

$Width = y + 4$

The New Area (A) is then calculated as:

$A = (x + 2) * (y + 4)$

Substitute $\frac{128}{y}$ for x

$A = (\frac{128}{y} + 2) * (y + 4)$

Open Brackets

$A = 128 + \frac{512}{y} + 2y + 8$

Collect Like Terms

$A = \frac{512}{y} + 2y + 8+128$

$A = \frac{512}{y} + 2y + 136$

$A= 512y^{-1} + 2y + 136$

To calculate the smallest possible value of y, we have to apply calculus.

Different A with respect to y

$A' = -512y^{-2} + 2$

Set

$A' = 0$

This gives:

$0 = -512y^{-2} + 2$

Collect Like Terms

$512y^{-2} = 2$

Multiply through by $y^2$

$y^2 * 512y^{-2} = 2 * y^2$

$512 = 2y^2$

Divide through by 2

$256=y^2$

Take square roots of both sides

$\sqrt{256=y^2$

$16=y$

$y = 16$

Recall that:

$x = \frac{128}{y}$

$x = \frac{128}{16}$

$x = 8$

Recall that the new dimensions are:

$Length = x + 2$

$Width = y + 4$

So:

$Length = 8 + 2$

$Length = 10$

$Width = 16 + 4$

$Width = 20$

To double-check;

Differentiate A'

$A' = -512y^{-2} + 2$

$A" = -2 * -512y^{-3}$

$A" = 1024y^{-3}$

$A" = \frac{1024}{y^3}$

The above value is:

$A" = \frac{1024}{y^3} > 0$

This means that the calculated values are at minimum.

<em>Hence, the dimensions of the smallest piece that can be used are: 10 by 20 and the area is 200 square inches</em>

3 0

3 years ago

Electric utility poles in the form of right cylinders are made out of wood that costs $25.46 per cubic foot. Calculate the cost

kotegsom [21]

Answer:

$ 1349.746624

Step-by-step explanation:

The volume of a cylinder

The formula for calculating the volume of a cylinder is expressed as:

V=πr²h

where:

r is the radius

h is the height

Given the following parameters

r = d/2 = 1.5/2 = 0.75ft

h = 30ft

Get the volume of the cylinder

V=π(0.75)²(30)

V= 53.0144...ft³

If the wod costs $25.46 per cubic foot, hence the cost of the wood will be 53.0144*25.46 = $ 1349.746624

4 0

2 years ago

X - 10 > 4x + 20 < x + 10

Delvig [45]

Answer:

Step-by-step explanation:

8 0

3 years ago

7.) A plane was flying at an altitude of 35,000 feet. It descended 6,000 feet to avoid some

worty [1.4K]

35,000 ft - 6,000 ft = 29,000 ft

4 0

2 years ago