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2 years ago

Solve number 8 please

Mathematics

1 answer:

beks73 [17]2 years ago

7 0

Answer:

see explanation

Step-by-step explanation:

the equation of a circle in standard form is

(x - h)² + (y - k )² = r²

where (h, k ) are the coordinates of the centre and r is the radius

given

x² + y² - 8x + 8y + 23 = 0

collect the x and y terms together and subtract 23 from both sides

x² - 8x + y² + 8y = - 23

using the method of completing the square

add ( half the coefficient of the x / y terms )² to both sides

x² + 2(- 4)x + 16 + y² + 2(4)y + 16 = - 23 + 16 + 16

(x - 4)² + (y + 4)² = 9 ← in standard form

with centre = (4, - 4 ) and r = $\sqrt{9}$ = 3

this is shown in graph b

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

larisa [96]

Answer: a) $(0.99)^4$

Step-by-step explanation:

Given : For safety reasons, four different alarm systems were installed in the vault containing the safety deposit boxes at a Beverly Hills bank.

Each of the four systems detects theft with a probability of .99 independently of the others .

Probability for independent events $(E_1 , E_2 , E_3 , ....., E_n)$ occurs together = $P(E_1)\times P(E_2)\times P(E_3)\ .....\times P(E_n)$ .

Then, the probability that when a theft occurs, all four systems will detect it

= (0.99) x (0.99) x (0.99) x (0.99)

$= (0.99)^4$

Hence, the probability that when a theft occurs, all four systems will detect it is $(0.99)^4$ .

Hence, the correct answer is a) $(0.99)^4$ .

5 0

3 years ago

An angle of 34°. If the arc is 162 feet tall, how far away is the bus? Round to the nearest tenth.

marta [7]

Answer:

the answer is 134 hope this helps.

8 0

3 years ago

Robert's dog is 4 years older than Karen's cat. In 3 years, the sum of the ages of Robert's dog and Karen's cat will be 13. How

mylen [45]

Answer:

5.5 years old.

Step-by-step explanation:

Let D represent present age of Robert's dog and C represent present age of Karen's cat.

We have been given that Robert's dog is 4 years older than Karen's cat. We can represent this information in an equation as:

$D=C+4...(1)$

We are also told that in 3 years, the sum of the ages of Robert's dog and Karen's cat will be 13. After 3 years age of dog and cat would be $D+3$ and $C+3$ respectively.

We can represent this information in an equation as:

$D+3+C+3=13...(2)$

From equation (1), we will get:

$C=D-4$

Upon substituting this value in equation (2), we will get:

$D+3+D-4+3=13$

Combine like terms:

$2D+2=13$

$2D+2-2=13-2$

$2D=11$

$\frac{2D}{2}=\frac{11}{2}$

$D=5.5$

Therefore, Robert's dog is 5.5 years old right now.

3 0

3 years ago

Can anyone solve this question??? plss plsss its my request to all if any one can solve this question I will mark him/ her the b

almond37 [142]

Answer:

a) ∠EAB = 180° - 90° - 30° = 60°

∠EBA = 180° - 90° - 60° = 30°

a) ∠EBA = 30°

b) ∠DCA = 180° - 90° - 30° = 60°

∠EBA ≅ ∠DAC, ∠EAB ≅ ∠DCA, ∠AEB ≅ ∠CDA

ΔEBA ≅ ΔDAC because of the AAA postulate

c) EB ≅ DA, EA ≅ DC, AB ≅ CA

d) AB = CA given

sin ∠EAB = EB/AB (sin 60°) EB = (0.8660)AB

cos ∠EAB = EA/AB (cos 60°) EA = (0.5)AB

cos ∠DAC = AD/CA (cos 30°) AD = (0.8660)CA

sin ∠DAC = CD/CA (sin 30°) CD = (0.5)CA

ED = EA + AD

ED = (0.5)AB + (0.8660)CA

since AB = CA, ED = 1.366CA

since EB = (0.8660)AB and AB = CA, then EB = 0.866CA

since CD = 0.5CA,

EB + CD = 0.866CA + 0.5CA = 1.366CA

EB + CD = 1.366CA

1.366CA = 1.366CA

Proof: ED = EB + CD

7 0

3 years ago

Statistics question about random probability Cheese pastureized or Raw MilkA cheese can be classified as either raw-milk or past

blsea [12.9K]

Answer:

(a) Two cheeses are chosen at random. the probability that both cheeses are pasteurized is Pr(PP) = 0.82 x 0.82 = 0.6724 to 4 decimal places)

(b) Four cheeses are chosen at random. The probability that all four cheeses are pasteurized is Pr(PPPP) = 0.82 x 0.82 x 0.82 x 0.82 = 0.4521 to 4 decimal places

(c) What is the probability that at least one of four randomly selected cheeses is raw-milk is Pr(RPPP) Or Pr(RRPP) Or Pr(RRRP) Or Pr(RRRR)

= 0.1269 to 4 decimal places

It would not be unusual that at least one of four randomly selected cheeses is raw-milk, because the probability have a value between 0 and 1

Step-by-step explanation:

If is given that 80% of the cheese is classified as pasteurized.

It then implies that 20% of the cheese is classified as Raw-milk

Probability of pasteurized cheese is 0.82(Denoted by Pr(P))

Probability of raw-milk cheese is 0.18(Denoted as Pr(R))

(a) Two cheeses are chosen at random. the probability that both cheeses are pasteurized is Pr(PP) = 0.82 x 0.82 = 0.6724 to 4 decimal places)

(b) Four cheeses are chosen at random. The probability that all four cheeses are pasteurized is Pr(PPPP) = 0.82 x 0.82 x 0.82 x 0.82 = 0.4521 to 4 decimal places

(c) What is the probability that at least one of four randomly selected cheeses is raw-milk is Pr(RPPP) + Pr(RRPP) + Pr(RRRP) + Pr(RRRR)

(0.18 x 0.82 x 0.82 x 0.82) + (0.18 x 0.18 x 0.82 x 0.82) + (0.18 x 0.18 x 0.18 x 0.82) + (0.18 x 0.18 x 0.18 x 0.18) = 0.1269 to 4 decimal places

3 0

3 years ago