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3 years ago

Does anyone know the answer?

Mathematics

1 answer:

Natali5045456 [20]3 years ago

7 0

Answer:

a = √5

b ∈ (−∞,∞)

Step-by-step explanation:

(7 + 3√5)/(3 + √5) - (7 - 3√5)/(3 - √5) = a + b√5

⇔ (7 + 3√5)(3 - √5)/(3 + √5)(3 -√5) - (7 - 3√5)(3 + √5)/(3 + √5)(3 -√5) = a + b√5

⇔ (7 + 3√5)(3 - √5) - (7 - 3√5)(3 + √5)/(3 + √5)(3 -√5) = a + b√5

⇔ 4√5/4 = a + b√5

⇔ √5 = a + b√5

⇔ b = (5 - a√5)/5

Replace b with (5 - a√5)/5

⇒ a + (5 - a√5)/5 = √5

⇔ a × 5 + (5 - a√5)(5)/5 = √5 × 5

⇔ a × 5 + 5 - a√5 = 5√5

⇔ a × 5 - √5 × a = 5√5 - 5

⇔ a(5 - √5) = 5√5 - 5

⇔ a = √5

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Step-by-step explanation:

(1/6)(-3x - 24) = -4

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=> -3x = 0

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=> -10x - 4 = -4 x 6

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Answer:

7) d)

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Step-by-step explanation:

solution:-

The Given data sample size 'n' = 81

Given Population standard deviation 'σ' = 1.8 hours

The standard error of the mean of one sample of 'n' observation is

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= $\frac{1.8}{\sqrt{81} } =0.2$

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The Given data sample size 'n' = 81

Given Population standard deviation 'σ' = 1.8 hours

Given the probability is 0.95

The z- score = 1.96 at 0.05 level of significance.

The margin of Error = $\frac{z_{0.95} S.D}{\sqrt{n} }$

= $\frac{1.96 (S.D)}{\sqrt{n} }$

= $\frac{1.96 (1.8)}{\sqrt{81} }$

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The 95% of confidence intervals are

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