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3 years ago

-2z+3-z=□-4z+2 please give me the answer

Mathematics

2 answers:

eduard3 years ago

4 0

<h3>Answer: z=-1</h3>

Step-by-step explanation:

$\displaystyle \rm -2z+3-z=-4z+2 \\\\ -3z+3=-4z+2 \\\\ 4z-3z=-3+2 \\\\ \underline{z=-1 \ \ \ \ } \\\\$

vovikov84 [41]3 years ago

4 0

$\large{\rm{\underline{\underline{Answer:}}}}$

Given to solve: -2z+3-z = -4z+2

⇛ -3z + 3 = -4z + 2

⇛ -3z + 4z = 2 - 3

⇛ <u>z = -1</u>

Required value of z is -1. The steps we followed are: We shifted z to a single side and other numbers to other side. Then we equated to get the result.

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Given the points (0,1) and (-2,5) and on a line, find its equation in the form y= mx+b.

AnnZ [28]

Answer:

the desired equation is y = -2x + 1

Step-by-step explanation:

As we go from (-2, 5) to (0, 1), x increases by 2 and y decreases by 4. Thus, the slope of this line is m = rise / run = -4 / 2, or m = -2.

Starting with y = mx + b, insert the knowns:

1 = -2(0) + b. Then b = 1, and the desired equation is y = -2x + 1.

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3 years ago

sixteen men working 9 hrs a day can complete a pice of work in 14 days .How many more men working 7 hrs a day would complete the

nordsb [41]

Answer:

<em>8 more men are needed to complete the job</em>

Step-by-step explanation:

<u>Proportions</u>

This problem can be solved by step-by-step reasoning applying proportions:

16 men working 9 hrs a day complete the job in 14 days
16 men working 1 hr a day complete the job in 14*9 days

The above statement stands because the fewer hours of work, the more time the job needs to be completed. Let's continue.

1 man working 1 hr a day complete the job in 14*9*16 days

The same reasoning applies here, fewer men=more days.

Now for the second condition. Increase the hours/day:

1 man working 7 hrs a day complete the job in 14*9*16/7 days

More hours/day=less days to complete the job

x men working 7 hrs a day complete the job in 14*9*16/(7*x) days

We know this last time is 12 days, thus:

$\displaystyle 12=\frac{14*9*16}{7*x}$

Solving for x:

$\displaystyle x=\frac{14*9*16}{7*12}=\frac{2016}{84}=24$

24 men are needed now, this is an increase of 24-16=8 more men

8 more men are needed to complete the job

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3 years ago

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OverLord2011 [107]

Answer:

Step-by-step explanation:

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3 years ago

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Of the total population of American households, including older Americans and perhaps some not so old, 17.3% receive retirement

Alex Ar [27]

Answer:

47.54% probability that more than 20 households but fewer than 35 households receive a retirement income

Step-by-step explanation:

We use the binomial aproxiation to the normal to solve this question.

Binomial probability distribution

Probability of exactly x sucesses on n repeated trials, with p probability.

Can be approximated to a normal distribution, using the expected value and the standard deviation.

The expected value of the binomial distribution is:

$E(X) = np$

The standard deviation of the binomial distribution is:

$\sqrt{V(X)} = \sqrt{np(1-p)}$

Normal probability distribution

Problems of normally distributed samples can be 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.

When we are approximating a binomial distribution to a normal one, we have that $\mu = E(X)$ , $\sigma = \sqrt{V(X)}$ .

In this problem, we have that:

$p = 0.173, n = 120$ . So

$\mu = E(X) = np = 120*0.173 = 20.76$

$\sigma = \sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{120*0.173*0.827} = 4.14$

In a random sample of 120 households, what is the probability that more than 20 households but fewer than 35 households receive a retirement income?

We are working with discrete values, so this is the pvalue of Z when X = 35-1 = 34 subtracted by the pvalue of Z when X = 20 + 1 = 21.

X = 34

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

$Z = \frac{34 - 20.76}{4.14}$