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3 years ago

How can you find f(3) if f(x) = -2x2 – 4?

Mathematics

2 answers:

Julli [10]3 years ago

8 0

Answer: f(3)=-20

Step-by-step explanation:

If you look at f(x) and f(3), you can see that 3 is in place of x. That means when x=3, what is f(x). You plug in x=3 into f(x) and solve.

f(3)=-2(3)²-2

f(3)=-2(9)-2

f(3)=-18-2

f(3)=-20

Citrus2011 [14]3 years ago

8 0

Answer:

-20

Step-by-step explanation:

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A cyclist rode the first 30-mile portion of his workout at a constant speed. For the 24-mile cooldown portion of his workout, he

LuckyWell [14K]

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3 0

2 years ago

An English professor assigns letter grades on a test according to the following scheme. A: Top 14% of scores B: Scores below the

NeX [460]

Answer:

Grades between 62 and 64 result in a D grade.

Step-by-step explanation:

Problems of normally distributed samples are solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

In this problem, we have that:

$\mu = 71.9, \sigma = 7.8$

Find the numerical limits for a D grade.

D: Scores below the top 84% and above the bottom 10%

So below the 100-84 = 16th percentile and above the 10th percentile.

16th percentile:

This is the value of X when Z has a pvalue of 0.16. So X when Z = -0.995.

$Z = \frac{X - \mu}{\sigma}$

$-0.995 = \frac{X - 71.9}{7.8}$

$X - 71.9 = -0.995*7.8$

$X = 64$

10th percentile:

This is the value of X when Z has a pvalue of 0.1. So X when Z = -1.28.

$Z = \frac{X - \mu}{\sigma}$

$-1.28 = \frac{X - 71.9}{7.8}$

$X - 71.9 = -1.28*7.8$

$X = 62$

Grades between 62 and 64 result in a D grade.

6 0

3 years ago

Find an equation of variation in which y varies inversely as x and y=5 and x=21. Then find the value of y when x=10.

finlep [7]

Answer:

see explanation

Step-by-step explanation:

Given that y varies inversely as x then the equation relating them is

y = $\frac{k}{x}$ ← k is the constant of variation

To find k use the condition y = 5 , x = 21

k = yx = 5 × 21 = 105

y = $\frac{105}{x}$ ← equation of variation

When x = 10, then

y = $\frac{105}{10}$ = 10.5

7 0

2 years ago

What is the change in y- values for every two units of x-values?

schepotkina [342]

Answer:

The graph of $y\:=\:\frac{1}{2}x$ is also attached below, which indicates that there is a change of only one unit on the y-axis for every two units of x-values.

Step-by-step explanation:

When there is a change in x values, it is basically a horizontal change. horizontal change between two values is also called the run.

And the vertically change between two values is also called the rise.

The slope is basically the ratio of the vertical (rise) and horizontal (run) changes between two points on a line.

For example, consider the equation

$y\:=\:\frac{1}{2}x$

$\mathrm{Slope\:of\:}\frac{1}{2}x:\quad m=\frac{1}{2}$

Here fore every two units of x-values, one units are moved on the y-axis.

In other words, there is a change of only one unit on the y-axis for every two units of x-values.

The graph of $y\:=\:\frac{1}{2}x$ is also attached below which is showing this.

5 0

2 years ago

A rectangular field has the area equal to that of a square field of side 60m.if the breadth of the rectangular field is 32m, fin

V125BC [204]

Given -

Area of rectangular field = Area of square field
side of square = 60m
breadth of the rectangular field = 32m

To find -

length of the rectangular field

Solution -

Area of square = side × side = (60 × 60)m² =

Area of square =3600m²

Hence,

Area of rectangular field = Area of square field = 3600m²

Area of rectangular field = l × b = 3600m²

=> l × 32m = 3600m²

=> l = $\sf{\frac{3600}{32}\:m}$

=> l = 112.5m

so, the length = 112.5m

5 0

2 years ago