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3 years ago

Please please help me!

Mathematics

1 answer:

julsineya [31]3 years ago

4 0

Answer:

x=19.2

Step-by-step explanation:

sin(28)=9/x

x=9/sin(28)

x=19.2

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2. Carl needs 15 hours longer than Jennifer to paint a room. If they work together, they can complete the job in 4 hours. Explai

nasty-shy [4]

Answer:

Jennifer would complete the job on her own in 5 hours.

Step-by-step explanation:

Solving a quadratic equation:

Given a second order polynomial expressed by the following equation:

$ax^{2} + bx + c, a\neq0$ .

This polynomial has roots $x_{1}, x_{2}$ such that $ax^{2} + bx + c = a(x - x_{1})*(x - x_{2})$ , given by the following formulas:

$x_{1} = \frac{-b + \sqrt{\Delta}}{2*a}$

$x_{2} = \frac{-b - \sqrt{\Delta}}{2*a}$

$\Delta = b^{2} - 4ac$

Rates

The together rate is the sum of their separates rate.

We have that:

Jennifer takes x hours to complete the job on her own, so her rate is 1/x.

Carl needs 15 hours longer than Jennifer, that is, 15 + x hours, so his rate is 1/(15+x).

The together rate is 1/4. So

$\frac{1}{4} = \frac{1}{x} + \frac{1}{15+x}$

$\frac{1}{4} = \frac{15 + x + x}{x(15+x)}$

$\frac{1}{4} = \frac{15 + 2x}{x(15+x)}$

Applying cross multiplication.

$x^2 + 15x = 4(15 + 2x)$

$x^2 + 15x = 60 + 8x$

$x^2 + 7x - 60 = 0$

Quadratic equation with $a = 1, b = 7, c = -60$ . So

$\Delta = 7^{2} - 4*1*60 = 289$

$x_{1} = \frac{-7 + \sqrt{289}}{2} = 5$

$x_{2} = \frac{-7 - \sqrt{289}}{2} = -12$

Since the time to complete the job has to be a positive value.

Jennifer would complete the job on her own in 5 hours.

4 0

2 years ago

What is the variance for 34, 46, 52, 29, 41, 38, 36, and 28

horsena [70]

Answer:

Step-by-step explanation:

add all the numbers and divide that number by the amount of numbers there.

34+46+52+29+41+38+36+28 / 8 = 304/8 = 38

8 0

3 years ago

Read 2 more answers

Complete the table and then graph the function.<br> y = 5x

sergejj [24]

Answer:

Coordinates: (0,0) ; (1,5) ; (2,10)

Step-by-step explanation:

x | y

0 0

1 5

2 10

Coordinates: (0,0) ; (1,5) ; (2,10)

This should be a straight line that is going diagonally with a positive slope.

7 0

2 years ago

ₜₕᵢₛ ₕₐₛ ₙₒ ₚₒᵢₙₜ ₜₒ ᵢₜ

Korvikt [17]

Answer:

Thanks for the points

Step-by-step explanation:

5 0

3 years ago

Please do #4 It’s it the one on the bottom

spin [16.1K]

We need to graph this equation:

$16x+2y=300$

Its solutions are the points through which it graph passes. Since it's a linear equation its graph is a straight line and we only need two of its points to draw it. But before graphing let's re-write the equation. We can substract 16x from both sides:

$\begin{gathered} 16x+2y=300 \\ 16x+2y-16x=300-16x \\ 2y=300-16x \end{gathered}$

And we divide both sides by 2:

$\begin{gathered} \frac{2y}{2}=\frac{300-16x}{2}=\frac{300}{2}-\frac{16x}{2} \\ y=150-8x \end{gathered}$

So now with this equation if we pick two random x values we'll get their corresponding y values. This way we'll find two points that are part of the graph which is the line that passes through both. We can begin with x=0:

$y=150-8\cdot0=150$

So the first point is (0,150). Then we can take x=10 and we get:

$y=150-8\cdot10=150-80=70$

So the second point is (10,70). Then the graph is the line that passes through points (0,150) and (10,70). In order to represent it

3 0

1 year ago