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3 years ago

Rewrite each expression as a polynomial in standard form.a)(x+i)(x-i)b)(x+5i)(x-5i)

Mathematics

1 answer:

Nitella [24]3 years ago

8 0

Answer:

a) x² +1

b) x² +25

Step-by-step explanation:

a) (x+i)(x− i)

= x² - ( i ) x + ( i ) x - ( i)²

= x² - i² ∵ i² = -1

= x² - (-1)

= x² +1

b) (x+5 i)(x− 5i)

= x² - ( 5 i ) x + ( 5 i ) x - ( 5 i)²

= x² - 25 i² ∵ i² = -1

= x² - 25(-1)

= x² +25

we can also solve

using identity

(a + b)(a - b) = a² - b²

= (x+5 i)(x− 5i)

= x² - (5 i)²

= x² - 25 i²

= x² +25

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A human resource manager wants to see if there is a difference in the proportion of minority applicants who get the job and the

mash [69]

Answer:

Error Bound = 0.04

Step-by-step explanation:

Whenever we want to estimate parameter from a subset (or sample) of the population, we need to considerate that your estimation won't be a 100% precise, in other words, the process will have a random component that prevents us from always making the exact decision.

With that in mind, the objective of a confidence interval is to give us a better insight of where we expect to find the "true" value of the parameter with a certain degree of certainty.

The estivamative of the true difference between proportions was -0.19 and the confidence interval was [-0.23 ; -0.15].

The question also defines the error bound, as the right endpoint of the confidence interval minus the sample mean difference, so it's pretty straight foward:

Error Bound = $-0.15 -(-0.19) = -0.15 + 0.19 = 0.04$

The interpretation of this would be that we expect that the estimative for the difference of proportions would deviate from the "true" difference about $\pm 0.04$ or 4%.

6 0

3 years ago

I need help with this math problem

mr Goodwill [35]

Let X = number of minutes.

Plan A = 50 + 0.04X

Plan B = 60 + 0.02X

50 + 0.04X = 60 + 0.02X

Subtract 50 from each side:

0.04X = 10 + 0.02X

Subtract 0.02X from each side:

0.02X = 10

Divide both sides by 0.02

X = 10 / 0.02

X = 500

It will take 500 minutes.

6 0

3 years ago

Prove x²+y² = (x+y) (x-y)

gtnhenbr [62]

Answer:

(x+y)(x-y)

x^2 - xy + xy - y^2

x^2 - y^2

7 0

2 years ago

Geometry please help asap!

m_a_m_a [10]

Step-by-step explanation:

AB = 3

by similaritiy criterion

CE/ CB= ED/AB

4/6= 2/AB

AB = 3

plz mark my answer as brainlist plzzzz also vote me ..if you find it useful.

6 0

3 years ago

For safety reasons, 4 different alarm systems were installed in the vault containing the safety deposit boxes at a Beverly Hills

Evgen [1.6K]

Answer:

99.93%

Step-by-step explanation:

Probability of Independent Events

Given the probability of success of each detector is 0.84 independently of the others, their combined success/failure probability can be computed with the product rule.

We can calculate the required probability by using the binomial distribution, but it's easier to calculate the probability of the negated event an subtract from 1.

We want to know the probability that a least one of the 4 systems detects the occurrence of theft. That probability is the sum of the probabilities that one of them, two of them, three of them or all of them succeed. The negated event is that NONE of them actually detects the theft. Being p the individual probability of success, p=0.84. Being q the probability of failure, q=0.16.

The probability that none of the systems detect the theft is

$P(0)=q^4=0.16^4=0.00065536$

Thus, the probability that at least one of the systems detect the theft is

$P(x\geq1)=1-P(0)=1-0.00065536=0.9993$

That means a 99.93%

3 0

3 years ago