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2 years ago

Write the equation of a line that passes through the point (-8,4) and is parallel to the line y=-5x+3.

Mathematics

1 answer:

Oduvanchick [21]2 years ago

5 0

Answer: y=-5x-36

Step-by-step explanation:

In order for two lines to be parallel they need to have the same slope. so the slope (m) of the new line needs to be -5.

slope(m) =-5

and the point (-8,4) is given to us. we can create a new equation for a line using the point slope formula because we have a slope (m=-5) and a point (-8,4)

point slope formula: y-y1=m(x-x1)

y-4=-5(x--8)

simplify and pay attention to negative signs

y-4=-5(x+8)

y-4=-5x-40

y=-5x-36

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Two airplanes leave an airport at the same time, the first headed due north and the second at a bearing of N42^ E . At 2:00PM, t

Leno4ka [110]

Answer:

The two airplanes are about 330miles apart.

Step-by-step explanation:

The diagram interpreting the question has been attached to this response.

As shown in the diagram,

i. the airplanes leave at point C.

ii. at 2.00pm the first and second airplanes are at points A and B respectively, where they are 312miles and 487miles away from the starting point C in directions due north and N42E from the point C.

iii. the points A, B and C form a triangle with sides a, b and c.

To solve for the value of c which is the distance between the two planes at 2.00pm, the cosine rule is used.

c² = a² + b² - 2abcosC --------------(i)

where;

b = 312miles

a = 487miles

C = 42°

Substitute these values into equation (i) and solve as follows;

c² = (487)² + (312)² - 2(312)(487)cos(42)

c² = (237169) + (97344) - 303888cos(42)

c² = (237169) + (97344) - 303888(0.7431)

c² = 334513 - 225819.1728

c² = 108693.8272

<em>Take the square root of both sides</em>

√c² = √108693.8272

c = 329.69

c ≅ 330miles

Therefore, the two airplanes are far apart by 330miles

3 0

3 years ago

a street light is at the top of a 18 ft tall pole. a woman 6 ft tall walks away from the pole with a speed of 4 ft/sec along a s

shutvik [7]

The most appropriate choice for similarity of triangles will be given by -

Speed of tip of the shadow of woman = 6 ft/s

What are similar triangles?

Two triangles are said to be similar, if the corrosponding angles of the triangles are same and the corrosponding sides of the triangles are in the same ratio.

Here,

The diagram has been attached here

Let the distance of woman from the pole be x ft and the distance of tip of the shadow to the pole be y ft.

Height of street light = 18 ft

Height of woman = 6ft

The two triangles are similar [As height of woman is parallel to the height of pole]

$\frac{y - x}{6}=\frac{y}{18}\\18y - 18x = 6y\\18y - 6y = 18x\\12y = 18x\\y = \frac{18}{12}x\\y = \frac{3}{2}x\\$

To find the speed, we have to differentiate both sides with respect to time 't'

$\frac{dy}{dt} =\frac{3}{2}\frac{dx}{dt}\\\frac{dy}{dt}=\frac{3}{2} \times 4\\\frac{dy}{dt} = 6$

Speed of tip of her shadow = 6 ft

To learn more about similarity of triangles, refer to the link-

brainly.com/question/14285697

#SPJ4

6 0

11 months ago

98-x2=0 solve this with the quadratic formula

Mars2501 [29]

Answer:

x∈{-7√2, 7√2}

Step-by-step explanation:

$98-x^2=0\\\\-x^2+98=0\\\\a=-1\,,\ \ b=0\,,\ \ c=98\\\\x_1=\dfrac{-0-\sqrt{0^2-4\cdot(-1)\cdot98}}{2\cdot(-1)}=\dfrac{-\sqrt{4\cdot49\cdot2}}{-2}=\dfrac{-2\cdot7\sqrt{2}}{-2}=7\sqrt2\\\\x_2=\dfrac{-0+\sqrt{0^2-4\cdot(-1)\cdot98}}{2\cdot(-1)}=\dfrac{2\cdot7\sqrt{2}}{-2}=-7\sqrt2$

7 0

2 years ago

The dwarves of the Grey Mountains wish to conduct a survey of their pick-axes in order to construct a 99% confidence interval ab

Dmitry_Shevchenko [17]

Answer:

The minimum sample size needed is 125.

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of $\pi$ , and a confidence level of $1-\alpha$ , we have the following confidence interval of proportions.

$\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}$

In which

z is the zscore that has a pvalue of $1 - \frac{\alpha}{2}$ .

The margin of error is:

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

For this problem, we have that:

$\pi = 0.25$

99% confidence level

So $\alpha = 0.01$ , z is the value of Z that has a pvalue of $1 - \frac{0.01}{2} = 0.995$ , so $Z = 2.575$ .

What minimum sample size would be necessary in order ensure a margin of error of 10 percentage points (or less) if they use the prior estimate that 25 percent of the pick-axes are in need of repair?

This minimum sample size is n.

n is found when $M = 0.1$