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4 years ago

BRAINLIEST, 5 STARS, 50 POINTS AND THANKS IF ANSWERED CORRECTLY.

Mathematics

2 answers:

Troyanec [42]4 years ago

7 0

Answer:

see explanation

Step-by-step explanation:

(1)

x² + 4 = 0 ( subtract 4 from both sides )

x² = - 4 ( take the square root of both sides )

x = ± $\sqrt{-4}$ = ± 2i ← complex solutions

(2)

x² - 81 = 0 ( add 81 to both sides )

x² = 81 ( take the square root of both sides )

x = ± $\sqrt{81}$ = ± 9 ← real solutions

Bas_tet [7]4 years ago

6 0

Answer:

1. -2

2. 9

Step-by-step explanation:

1. 0 = x2 + 4

-4 = x2

$\sqrt{-4}$ = x

x = -2

2. 0 = x2 - 81

81 = x2

$\sqrt{81}$ = x

x = 9

MARK IT BRAINLIEST!!!

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What is the product?

ZanzabumX [31]

Answer:

The product is:

$\left[\begin{array}{cc}15 & 14\\-1 & 9\end{array}\right]$

Step-by-step explanation:

For this problem you need to multiply the first row only for the two first column of the others matrix and get the desired result:

$\left[\begin{array}{ccc}1&3&1\\-2&1&0\end{array}\right] \times \left[\begin{array}{cc}2&-2\\3&5\\4&1\end{array}\right]$

$1 \times 2 + 3 \times 3 + 1 \times -2 = 15$

So the value of the element in the position $a_{11}$ is 15

$1 \times -2 + 3 \times 5 + 1 \times 1 = 14$

So the value of the element in the position $a_{12}$ is 14

Then with these two values you can determinate the result matrix.

$\left[\begin{array}{cc}15 & 14\\-1 & 9\end{array}\right]$

3 0

3 years ago

A refrigerator cools a bottle of water 2 degrees per minute. how many minutes will it take to lower its temperature from 90 degr

HACTEHA [7]

<span>It will take 20 minutes. The fridge needs to cool down by 90-50=40degrees. The fridge cools at 2 degrees per minute, i.e. 40/2=20 minutes total.</span>

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3 years ago

You will need the same dataset used for problem 3 in homework 1 (the dataset obtained from the yahoo website with the company yo

stepladder [879]

Answer:

a) The probability of sampling at random a fish that is smaller in size than the value you would obtain by subtracting half the standard deviation from the average is 0.3085.

b) The probability of sampling at random a fish that is greater in size than the value you would obtain by adding half the standard deviation from the average is 0.3085.

c) The probability of sampling at random a fish that has a size between the two values is 0.383.

d) The 25th and 75 percentiles of fish size for the population using the normal distribution table is 5.69 and 5.87 respectively.

e) The probability that the average calculated will be less than the value is 0.3707.

Step-by-step explanation:

For the given data set mean $(\mu) = 5.75913$