How many lines of symmetry does the quadrilateral below have.

If f(x) = 2x squared - 5x + 7 what is the value of f(-3)

ch4aika [34]

Answer:

f(-3)=40

Step-by-step explanation:

4 0

2 years ago

"A cable TV company wants to estimate the percentage of cable boxes in use during an evening hour. An approximation is 20 percen

Marizza181 [45]

Answer:

The company should take a sample of 148 boxes.

Step-by-step explanation:

Hello!

The cable TV company whats to know what sample size to take to estimate the proportion/percentage of cable boxes in use during an evening hour.

They estimated a "pilot" proportion of p'=0.20

And using a 90% confidence level the CI should have a margin of error of 2% (0.02).

The CI for the population proportion is made using an approximation of the standard normal distribution, and its structure is "point estimation" ± "margin of error"

[p' ± $Z_{1-\alpha /2} * \sqrt{\frac{p'(1-p')}{n} }$ ]

Where

p' is the sample proportion/point estimator of the population proportion

$Z_{1-\alpha /2} * \sqrt{\frac{p'(1-p')}{n} }$ is the margin of error (d) of the confidence interval.

$Z_{1-\alpha /2} = Z_{1-0.05} = Z_{0.95}= 1.648$

So

$d= Z_{1-\alpha /2} * \sqrt{\frac{p'(1-p')}{n} }$

$d *Z_{1-\alpha /2}= \sqrt{\frac{p'(1-p')}{n} }$

$(d*Z_{1-\alpha /2})^2= \frac{p'(1-p')}{n}$

$n*(d*Z_{1-\alpha /2})^2= p'(1-p')$

$n= \frac{p'(1-p')}{(d*Z_{1-\alpha /2})^2}$

$n= \frac{0.2(1-0.2)}{(0.02*1.648)^2}$

n= 147.28 ≅ 148 boxes.

I hope it helps!

3 0

3 years ago

If 10% of x is 30, what is 23% of x A. 33 B. 46 C. 200 D. 230

aliina [53]

Answer:

69

Step-by-step explanation:

I'm mathematics, the word 'of' transfers into becoming 'times or Multiply'

Therefore, the expression can be rewritten as:

10/100 of x = 30

10x / 100 = 30

Cross Multiply the equation to solve for x

10x = 100 * 30

10x = 3000

x = 3000 / 10

x = 300

(Since we gotten the value of x as 300) let's find 23% of it.

Therefore,

23% of x, ( when x is 300)

= 23/100 * 300

= 23 * 3

= 69

(Well, although that's the workable solution, the option doesn't seen to tally)

Maybe you check the source, but am certain about the Solution.

Let's keep learning, maths is fun !

3 0

3 years ago

Read 2 more answers

Enter a recursive rule for the geometric sequence. 6, −18, 54, −162, ...

svlad2 [7]

Answer:

The required recursive formula is:

$a_n=(-3)\times a_{n-1}$

Step-by-step explanation:

We are given a geometric sequence as:

6,-18,54,-162,.....

Clearly after looking at different terms of the sequence we could observe that the sequence is an geometric progression (G.P.) with common ratio= -3 denoted by r.

Let $a_n$ represents the nth term of the sequence.