What is the answer the this question??????

Use the square root property to solve x^2-9=0<br> Please help and please show work if you can

charle [14.2K]

Answer:

x = 3 or -3

Step-by-step explanation:

So you have the equation x² - 9 = 0

Move the 9 to the other side: x² = 9

Then take the square root of both sides: $\sqrt{x^{2} }$ = ± $\sqrt{9}$

x = ± $\sqrt{9}$ = ±3

x = 3 or -3

6 0

2 years ago

Read 2 more answers

The graph is of a polynomial function f(x) of degree 5 whose leading coefficient is 1. The graph is not drawn to scale. Use the

LUCKY_DIMON [66]

roots of a polynomial are (x-c1)(x-c2)(x-c3) .......(x-cn). Basically, plug every root you have into a (x-__) and then multiply them all together. Just be careful of signs. If your root is positive, it is written as (x-__). If your root is negative, it is written (x+__)

<span>Hope this helps</span>

7 0

2 years ago

In describing a dataset, what does the standard deviation or standard error represent?

ivann1987 [24]

A measure of the variation around the estimate of the mean.

The standard deviation is a statistic that lets you know how tightly all the subjects are clustered around the mean in a set of data. A single standard deviation away from the mean in either of the directions accounts for somewhere around 68 % of data. If two standard deviations are away from the mean, it accounts for around 95% of data. If three standard deviations are away it accounts for 99% of the data.

1) The total range of variation in the dataset is called RANGE.

3) A measure of the variation around the estimate of the mean is SEM (STANDARD ERROR OF THE MEAN).

4) The most common value observed (highest frequency) is MODE.

7 0

3 years ago

Students have organized

Olenka [21]

Answer:

Part A. At least 6 hours

Part B. In less than 2.5 hours Elijah will be behind Mercedes

Part C. In more than 2.5 hours Elijah will be ahead Aubrey

Step-by-step explanation:

D = distance

v =speed

t = time

Formula connecting D, v and t:

$D=v\cdot t$

Part A.

Steve's speed: $v=3.5\ mph$

Distance: at least 21 miles

Time: unknown, so

$3.5\cdot t\ge 21\\ \\35t\ge 210\ [\text{Multiplied by 10}]\\ \\t\ge \dfrac{210}{35}\\ \\t\ge \dfrac{30}{5}\\ \\t\ge 6$

It would take Steve at least 6 hours to walk at least 21 mi on Day 1.

Part B.

Mercedes's speed: $v_M=2.4\ mph$

Elijan's speed: $v_E=3.2\ mph$

Elijan's Distance walked: $D_E$ miles

Mercedes's Distance walked: $D_M$ miles

Time: x hours

Mercedes is 2 miles ahead, so

$D_E=3.2x\\ \\D_M=2.4x+2$

Elijan will be behind when

$D_E$

In 2.5 hours Elijan will catch up Mercedes, and in less than 2.5 hours Elijah will be behind Mercedes.

Part C.

Aubrey's speed: $v_M=3\ mph$

Elijan's speed: $v_E=3.2\ mph$

Elijan's Distance walked: $D_E$ miles

Aubrey's Distance walked: $D_A$ miles

Time: x hours

At the beginning of Day 3, Elijah starts walking at the marker for Mile 42, and Aubrey starts walking at the marker for Mile 42.5.

$D_E=42+3.2x\\ \\D_A=42.5+3x$

Elijan will be ahead of Aubrey when

$D_E>D_A\\ \\42+3.2x> 42.5+3x\\ \\3.2x-3x>42.5-42\\ \\0.2x>0.5\\ \\2x>5\ [\text{Multiplied by 10}]\\ \\x>\dfrac{5}{2}\\ \\x>2.5\ hours$

In 2.5 hours Elijan will catch up Aubrey, and in more than 2.5 hours Elijah will be ahead Aubrey.

4 0

3 years ago

Which of the following fitness scores is the highest relative score?

evablogger [386]

Due to the higher z-score, the correct option regarding the highest relative score is:

A score of 4730 on a test with a mean of 3960 and a standard deviation of 555.5.

<h3>What is the z-score formula?</h3>

The z-score of a measure X of a normally distributed variable with mean $\mu$ and standard deviation $\sigma$ is given by:

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

The z-score measures how many standard deviations the measure is above or below the mean, hence the higher the z-score, the higher the score X is relative to other scores.

The respective z-scores for this problem are given by:

(39 - 31)/6.1 = 1.31.

(1136 - 1080)/67.8 = 0.83.

(4730 - 3960)/555.5 = 1.39.

Hence the correct option is:

A score of 4730 on a test with a mean of 3960 and a standard deviation of 555.5.

More can be learned about z-scores at brainly.com/question/28096232

#SPJ1

6 0

2 years ago