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3 years ago

Factorise (m+3)^2 - 16

Mathematics

1 answer:

Akimi4 [234]3 years ago

5 0

(m + 3)^2 -16

=(m + 3)^2 - 4^2

=((m+3) + 4)*((m+3) - 4)

=(m+7)(m-1)

Here are the formulas i used:

so first i made 16 to 4^2, then i use (a^2 -b^2)= (a+b)(a-b) . In this case a would be (m+3) and b is 4.

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The question is incomplete! Complete question along with answer and step by step explanation is provided below.

Question:

The lifetime (in hours) of a 60-watt light bulb is a random variable that has a Normal distribution with σ = 30 hours. A random sample of 25 bulbs put on test produced a sample mean lifetime of = 1038 hours.

If in the study of the lifetime of 60-watt light bulbs it was desired to have a margin of error no larger than 6 hours with 99% confidence, how many randomly selected 60-watt light bulbs should be tested to achieve this result?

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Required Information:

sample size = n = ?

Answer:

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Step-by-step explanation:

We know that margin of error is given by

Margin of error = z*(σ/√n)

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3 years ago

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3 years ago

Factorise (m+3)^2 - 16​

Factorise (m+3)^2 - 16