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3 years ago

Evaluate 13 - 0.75w + 8z when w = 12 and x = 1/2

Mathematics

1 answer:

geniusboy [140]3 years ago

4 0

Answer:8

Step-by-step explanation:

You might be interested in

NASA launches a rocket at t = 0 seconds. Its height, in meters above sea-level, as a function of time is given by h ( t ) = − 4.

Oliga [24]

Answer:

$\displaystyle 1)48.2 \: \: \text{sec}$

$\rm \displaystyle 2)3021.6 \: m$

Step-by-step explanation:

<h3>Question-1:</h3>

so when flash down occurs the rocket will be in the ground in other words the elevation(height) from ground level will be 0 therefore,

to figure out the time of flash down we can set h(t) to 0 by doing so we obtain:

$\displaystyle - 4.9 {t}^{2} + 229t + 346 = 0$

to solve the equation can consider the quadratic formula given by

$\displaystyle x = \frac{ - b \pm \sqrt{ {b}^{2} - 4 ac} }{2a}$

so let our a,b and c be -4.9,229 and 346 Thus substitute:

$\rm\displaystyle t = \frac{ - (229) \pm \sqrt{ {229}^{2} - 4.( - 4.9)(346)} }{2.( - 4.9)}$

remove parentheses:

$\rm\displaystyle t = \frac{ - 229 \pm \sqrt{ {229}^{2} - 4.( - 4.9)(346)} }{2.( - 4.9)}$

simplify square:

$\rm\displaystyle t = \frac{ - 229 \pm \sqrt{ 52441- 4( - 4.9)(346)} }{2.( - 4.9)}$

simplify multiplication:

$\rm\displaystyle t = \frac{ - 229 \pm \sqrt{ 52441- 6781.6} }{ - 9.8}$

simplify Substraction:

$\rm\displaystyle t = \frac{ - 229 \pm \sqrt{ 45659.4} }{ - 9.8}$

by simplifying we acquire:

$\displaystyle t = 48.2 \: \: \: \text{and} \quad - 1.5$

since time can't be negative

$\displaystyle t = 48.2$

hence,

at 48.2 seconds splashdown occurs

<h3>Question-2:</h3>

to figure out the maximum height we have to figure out the maximum Time first in that case the following formula can be considered

$\displaystyle x _{ \text{max}} = \frac{ - b}{2a}$

let a and b be -4.9 and 229 respectively thus substitute:

$\displaystyle t _{ \text{max}} = \frac{ - 229}{2( - 4.9)}$

simplify which yields:

$\displaystyle t _{ \text{max}} = 23.4$

now plug in the maximum t to the function:

$\rm \displaystyle h(23.4)- 4.9 {(23.4)}^{2} + 229(23.4)+ 346$

simplify:

$\rm \displaystyle h(23.4) = 3021.6$

hence,

about 3021.6 meters high above sea-level the rocket gets at its peak?

5 0

2 years ago

The angle of elevation from a buoy in the water to the top of a lighthouse is 68degrees. If a buoy is 300 ft from the base of th

Katen [24]

Answer:

The height of the lighthouse is $742.5\ ft$

Step-by-step explanation:

Let

h -----> the height of the lighthouse

we know that

The tangent of angle of 68 degrees is equal to divide the height of the lighthouse by the horizontal distance from the buoy to the base of lighthouse

$tan(68\°)=\frac{h}{300}$

Solve for h

$h=(300)tan(68\°)=742.5\ ft$

7 0

3 years ago

In the data set #2 {75,80,85,75,85}, what is the mean?

Fantom [35]

Answer:

Step-by-step explanation:

7 0

2 years ago

In a survey, three out of four students said that courts show too much concern for criminals. Of seventy randomly selected stude

vladimir1956 [14]

Answer:

B. Yes, because P(X ≥ 68) ≤ .05

Step-by-step explanation:

The probability of a score X occuring is said to be unusually high if the probability of a score of X or larger is lower than 5%.

For each student, there are only two possible outcomes. Either they think that the court shows too much concern for criminals, or they do not think this. So we use the binomial probability distribution to solve this problem.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

In which $C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by the following formula.

$C_{n,x} = \frac{n!}{x!(n-x)!}$

And p is the probability of X happening.

In this problem we have that:

Three out of four students said that courts show too much concern for criminals. This means that $p = \frac{3}{4} = 0.75$

Would 68 be considered an unusually high number of students who feel that courts are partial to criminals?

We have to find $P(X \geq 68)$ .

$P(X \geq 68) = P(X = 68) + P(X = 69) + P(X = 70)$

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 68) = C_{70,68}.(0.75)^{68}.(0.25)^{2} < 0.000001$

$P(X = 69) = C_{70,69}.(0.75)^{69}.(0.25)^{1} < 0.000001$

$P(X = 70) = C_{70,70}.(0.75)^{70}.(0.25)^{0} < 0.000001$

$P(X \geq 68) = P(X = 68) + P(X = 69) + P(X = 70) < 0.000003$

$P(X \geq 68)$ is lower than 0.05, so this is an unusually high number.

So the correct answer is:

B. Yes, because P(X ≥ 68) ≤ .05

5 0

3 years ago

3 + x < 7 possible sloution for this

krok68 [10]

Answer: x<4

Step-by-step explanation:

Step 1: Simplify both sides of the inequality.

x+3<7

Step 2: Subtract 3 from both sides.

x+3−3<7−3

x<4

8 0

2 years ago