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3 years ago

12

HELP beautiful people that know how to do these problems <3

1 answer:

kenny6666 [7]3 years ago

8 0

The answers are:

1. $4 + b$

2. $8(x + 3)$

3. $25 + 1.5d$

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Give an equivalent expression for each problem

lord [1]

Answer:1. 4x^2-3x-6

2. 4x^2+7x-8

3. Is the same problem as #2

Step-by-step explanation:

4 0

3 years ago

The first descended to 86 feet below the cave opening. The second descended 22 feet less then the first. What expression can be

pogonyaev

1st guy minus the 2nd is how far the 2nd made it
86-22=64 ft

4 0

2 years ago

A 22.5<br> B 7.25<br> C 7.5<br> D 30

cluponka [151]

The answer is D. 30 because you multiple 15 times 2

4 0

2 years ago

I do not understand the final part of this question?

jolli1 [7]

AB=CD (given)

AB=AM+DM (M is mied point of AB&CD

CD can be writen as AM+DM)

8 0

2 years ago

If a light bulb manufacturing company wants to estimate, with 99% confidence, the mean life of compact fluorescent light bulb

Reptile [31]

Answer:

We need at least 217 compact fluorescent light bulbs

Step-by-step explanation:

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1-0.99}{2} = 0.005$

Now, we have to find z in the Ztable as such z has a pvalue of $1-\alpha$ .

So it is z with a pvalue of $1-0.005 = 0.995$ , so $z = 2.575$

Now, find M as such

$M = z*\frac{\sigma}{\sqrt{n}}$

In which $\sigma$ is the standard deviation of the population and n is the size of the sample.

How many compact fluorescent light bulbs need to be selected?

We need at least n bulbs, in which n is found when $M = 175, \sigma = 1000$

So

$M = z*\frac{\sigma}{\sqrt{n}}$

$175 = 2.575*\frac{1000}{\sqrt{n}}$

$175\sqrt{n} = 2575$

$\sqrt{n} = \frac{2575}{175}$

$\sqrt{n} = 14.71$

$\sqrt{n}^{2} = (14.71)^{2}$

$n = 216.5$

We need at least 217 compact fluorescent light bulbs

4 0

3 years ago

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