All categories

3 years ago

3. Decide whether each equation is true or false, and explain how you know.

Mathematics

1 answer:

BARSIC [14]3 years ago

5 0

Answer:

a.false

b.true

c.false

d.I really can't get about it.

e.false

Step-by-step explanation:

So,here;

a.9.9.3=35 is given

or,243=35 (which is false)

b.7+7+7=3+3+3+3+3+3+3

or,21=21 (which is true)

c.2/3/2=2/3

or,2*2/3=2/3

or,4/3=2/3(which is false)

e.6+6+6=63

or,18=63 (which is false)

You might be interested in

Help me please i dont understand

ELEN [110]

Answer:

6/5 or 1.2, they're the same value

Step-by-step explanation:

When it says "rate of change", it's really just asking for the slope. If you don't know what the slope is, essentially how much the y-value increases by whenever x increases by 1. This can be formally defined using the equation: $\frac{y_2-y_1}{x_2-x_1}$ which is essentially $\frac{rise}{run}$ . The subtraction is finding the difference between the two numbers to see how much it's changed by. Btw the order doesn't matter, I could plug in (-3, -2) as (x2, y2) or I could plug it in as (x1, y1) as long as I make sure to input it in correctly. In this example I'll just say (-3, -2) = (x1, y1) and (2, 4) = (x2, y2). Plugging these values into the equation gives you: $\frac{4- (-2)}{2- (-3)} = \frac{6}{5}$ that's the rate of change

8 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 $M = 0.1$

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

$0.1 = 2.575\sqrt{\frac{0.25*0.75}{n}}$

$0.1\sqrt{n} = 2.575{0.25*0.75}$

$\sqrt{n} = \frac{2.575{0.25*0.75}}{0.1}$

$(\sqrt{n})^{2} = (\frac{2.575{0.25*0.75}}{0.1})^{2}$

$n = 124.32$

Rounding up

The minimum sample size needed is 125.

5 0

4 years ago

If each foot of water in a lake screens out 60% of the light above, what percent of the light passes through 5 feet of water?

BartSMP [9]

The amount of light passing through each foot the water in the lake = 100% - 60% = 40%
The percent of light passing through 5 feet of water = 0.4^5 = 0.01024 = 1.02%

8 0

3 years ago

a line is perpendicular to y = 3/7x - 2 and intersects the point (3,3). What is the equation of this perpendicular line?

snow_lady [41]

Answer:

y = -7/3x + 10

Step-by-step explanation:

Step 1: Find the slope of the perpendicular line

Do this by taking the negative inverse of the first line

m = -7/3

Step 2: Find <em>b</em>

y = mx + b

y = -7/3x + b

3 = -7/3(3) + b

3 = -7 + b

b = 10

You should get y = -7/3x + 10 as your final answer.

6 0

3 years ago

The sum of two integers is 26. the sum of the squares of the two integers is 340. what is the product of the two numbers?

Phoenix [80]

Lets say that the two unknown integers are $n$ and $m$ .

We know the following things about $n$ and $m$ :

$n+m=26$
$n^2+m^2=340$

And, we want to find $nm$ .

To solve this, we'll use the expansion of the squared of the sum of any two inegers; this is expressed as:

$(n+m)^2=n^2+2nm+m^2$

So, given what we know about the unknown integers, the previous can be written as:

$(26)^2=340+2nm$

We can easily solve for $nm$ :

$nm= \frac{(26)^2-340}{2}= \frac{676-340}{2}= \frac{336}{2}=168$

The answer is 168.

Another approach to solve the problem is, from the two starting equations, compute the values of $n$ and $m$ , which are 12 and 14, and directly compute their product; however, the approach described is more elegant.

5 0

3 years ago