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3 years ago

Is the proportion A, B, D, or D?

Mathematics

1 answer:

Oksanka [162]3 years ago

3 0

Answer:

C.)

Step-by-step explanation:

4/20=8/x

You might be interested in

A cable hangs between two poles of equal height and 35 feet apart. At a point on the ground directly under the cable and x feet

gayaneshka [121]

Answer:

293.38 pounds

Step-by-step explanation:

We are given that

Distance between poles=35 feet

$h(x)=10+0.1(x^{1.5})$

Weight of cable=10.4 per linear foot

We have to find the weight of the cable.

Differentiate w.r.t

$h'(x)=0.1(1.5)x^{0.5}=0.15x^{0.5}$

$s=2\int_{0}^{17.5}\sqrt{1+(h'(x))^2}dx$

$s=2\int_{0}^{17.5}\sqrt{1+(0.15x^{0.5})^2}dx$

$s=2\int_{0}^{17.5}\sqrt{1+0.0225x}dx$

Let $1+0.0225x=t$

$dx=\frac{1}{0.0225}dt$

$s=\frac{2}{0.0225}\int_{0}^{17.5}\sqrt{t}dt$

$s=\frac{2}{0.0225}\times\frac{2}{3}[t^{\frac{3}{2}}]^{17.5}_{0}$

$s=2\times \frac{2}{3\times0.0225}[(1+0.0255x)^{\frac{3}{2}]^{17.5}_{0}$

$s=\frac{4}{3\times 0.0225}((1+0.0225(17.5))^{\frac{3}{2}-1)$

s=28.21

Weight of cable= $28.21\times 10.4=293.38$ pound

8 0

3 years ago

PLEASE HELP. WILL GIVE BRAINLIEST

KengaRu [80]

Answer:

x-intercepts = 1,2, and 4, y-intercept = -8

Step-by-step explanation:

x^3 - 7x^2 - 14x - 8 in factored form is equal to (x-1)(x-2)(x-4).

Solving for x-intercepts:

We are actually able to solve for all x-intercepts without the given factor. But since we are given one of the factors, our job becomes much easier.
Using synthetic division, or long division, we factor out the x-intercept 4. Which leaves us with the polynomial x^2 - 3x + 2.
From here we can separate the polynomial into two binomials.
x^2 - 3x + 2 = (x-1)(x-2). Giving us all 3 x-intercepts.
Using Descartes' rules we can identify before even starting the problem how many real x-intercepts there are (Not needed for this problem).

Solving for y-intercept:

The y-intercept is always the coefficient that does not have any assigned x-variables.
The coefficient is -8, thus the y-intercept.
If unsure of the y-intercept, you can always plug in x = 0. Solving for the y-intercept will give you the value of f(0).
If there is no coefficient, the y-intercept is equal to zero.

4 0

3 years ago

Rationalize the denominator of sqrt -49 over (7 - 2i) - (4 + 9i)

zubka84 [21]

$\sqrt{ \frac{-49}{(7-2i)-(4+9i) } } 
$

This one is quite the deal, but we can begin by distributing the negative on the denominator and getting rid of the parenthesis:

$\frac{ \sqrt{-49}}{7-2i-4-9i}$

See how the denominator now is more a simplification of like terms, with this I mean that you operate the numbers with an "i" together and the ones that do not have an "i" together as well. Namely, the 7 and the -4, the -2i with the -9i.
Therefore having the result:

$\frac{ \sqrt{-49} }{3-11i}$

Now, the $\sqrt{-49}$ must be respresented as an imaginary number, and using the multiplication of radicals, we can simplify it to $\sqrt{49} \sqrt{-1}$
This means that we get the result 7i for the numerator.

$\frac{7i}{3-11i}$

In order to rationalize this fraction even further, we have to remember an identity from the previous algebra classes, namely: $x^2 - y^2 =(x+y)(x-y)$
The difference of squares allows us to remove the imaginary part of this fraction, leaving us with a real number, hopefully, on the denominator.

$\frac{7i (3+11i)}{(3-11i)(3+11i)}$

See, all I did there was multiply both numerator and denominator with (3+11i) so I could complete the difference of squares.
See how $(3-11i)(3+11i)= 3^2 -(11i)^2$ therefore, we can finally write:

$\frac{7i(3+11i)}{3^2 - (11i)^2 }$

I'll let you take it from here, all you have to do is simplify it further.
The simplification is quite straightforward, the numerator distributed the 7i. Namely the product $7i(3+11i) = 21i+77i^2$ .
You should know from your classes that i^2 = -1, thefore the numerator simplifies to $-77+21i$
You can do it as a curious thing, but simplifying yields the result:
$\frac{-77+21i}{130}$

7 0

3 years ago

A basketball player shoots a basketball that reaches a height above 15 feet before landing back on the ground exactly after 7 se

Papessa [141]

Answer:

I and IV

Step-by-step explanation:

Since the height of the basketball reaches above 15 feet, hence the maximum of the function should be greater than 15 feet. Also at 7 seconds, the ball is on the ground, hence f(7) = 0 feet

The maximum of a function is at x = -b/2a

i) f(x) = -(x-3)² + 16 = -(x² - 6x + 9) + 16 = -x² + 6x + 7

The maximum of a function is at x = -b/2a = -6 / 2(-1) = 3

f(3) = -(3-3)² + 16 = 16 > 15

Also f(7) = - (7 - 3)² + 16 = 0

Hence this option is correct

ii) f(x) = -x² + 8x - 7

The maximum of a function is at x = -b/2a = -8 / 2(-1) = 4

f(4) = -4² + 8(4) - 7 = 9 < 15 not correct

Also f(7) = - 7² + 8(7) - 7 = 0

Hence this option is not correct since the maximum f(4) = 9 < 15

iii) f(x) = -(x-3)² + 14 = -(x² - 6x + 9) + 14 = -x² + 6x + 5