What multiples to 42 and adds to -2

Mathematics

1 answer:

solniwko [45]4 years ago

4 0

Answer:

Step-by-step explanation:

xy = 42

x+y = - 2 Substitute into the top equation

y = -2 - x Put in for y

x(-2 - x) = 42 Remove the brackets

-2x - x^2 = 42 Subtract 42 from both sides.

-2x - x^2 - 42 = 0 Put in the more normal order.

-x^2 - 2x - 42 = 0 Multiply by -1

x^2 + 2x + 42 = 0

This cannot be factored. It gives complex roots as it is written. I will give you the answer but I kind of doubt the question is correct.

x1 = - 1 + 6.40i

x2 = -1 - 6.40i

Leave a comment if you have a correction.

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The lengths of a particular snake are approximately normally distributed with a given mean mc025-1.jpg = 15 in. and standard dev

Vedmedyk [2.9K]

Answer:

2.5% of the snakes are longer than 16.6 in

Step-by-step explanation:

The Z score is,

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

here,

X = raw score = 16.6

μ = mean = 15

σ = standard deviation = 0.8

So,

$Z=\dfrac{16.6-15}{0.8}=2$

Z-score is the measurement of how many standard deviation away the data is from the mean. Hence, the value 16.6 is 2 standard deviations right to the mean.

Approximately 95% of the data falls within two standard deviations of the mean. (between the mean-2 times the standard deviation, and the mean+2 times the standard deviation)

So the 5% of data are left in the remaining space. As we have to find the amount of snakes which are longer than 16.6 in i.e we have to find the area to the right of 16.6.

The remaining 5% of amount is divided in two equal parts.

Therefore, $\dfrac{5}{2}=2.5\%$ of the snakes are longer than 16.6 in