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PSYCHO15rus [73]
3 years ago
13

Which of the following is a solution of x2 − 2x = −8? (6 points) Select one: a. negative 1 minus i square root of 28 b. 1 plus i

square root of 28 c. negative 1 minus i square root of 7 d. 1 plus i square root of 7
Mathematics
1 answer:
crimeas [40]3 years ago
3 0
X = 2 +- √4 -32 )/2 = 1 +-i√7

Answer is <span>d. 1 plus i square root of 7

Hope it helps!
</span>
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How would the expression x^2-4 be rewritten using Difference of Squares?
Anna [14]
<span>a2 – b2 = (a + b)(a – b) or (a – b)(a + b).
This is the 'Difference of Squares' formula we can use to factor the expression.

In order to use the </span><span>'Difference of Squares' formula to factor a binomial, the binomial must contain two perfect squares that are separated by a subtraction symbol.

</span><span>x^2 - 4 fits this, because x^2 and 4 are both perfect squares, and they are separated by a subtraction symbol.
All you do here to factor, is take the square root of each term.

√x^2 = x
√4 = 2

Now that we have our square roots, x and 2, we substitute these numbers into the form (a + b)(a - b).
</span>
<span>(a + b)(a - b)
(x + 2)(x - 2)

Our answer is final </span><span>(x + 2)(x - 2), which can also be written as (x - 2)(x + 2), it doesn't make a difference which order you put it in.

Anyway, Hope this helps!!
Let me know if you need help understanding anything and I'll try to explain as best I can.</span>
3 0
3 years ago
A study has indicated that the sample size necessary to estimate the average electricity use by residential customers of a large
Zanzabum

Answer:

\sigma=547.1125

Step-by-step explanation:

-The margin of error is calculated using the formula:

ME=z_{\alpha/2}\times \frac{\sigma}{\sqrt{n}}\\\\

-We substitute the values, n=900 and ME=30 in the formula to solve for standard deviation:

ME=z_{\alpha/2}\times \frac{\sigma}{\sqrt{n}}\\\\\\30=1.645\times\frac{\sigma}{\sqrt{900}}\\\\\sigma=\frac{30^2}{1.645}\\\\=547.1125

Hence, the population standard deviation is 547.1125

7 0
3 years ago
What is the solution to the system of equations?
MariettaO [177]

Answer:

x=-4 y=-1

Step-by-step explanation:

Let's solve your system by substitution.

−3x−8y=20;y=5x+19

Rewrite equations:

y=5x+19;−3x−8y=20

Step: Solve y=5x+19for y:

y=5x+19

Step: Substitute5x+19foryin−3x−8y=20:

−3x−8y=20

−3x−8(5x+19)=20

−43x−152=20(Simplify both sides of the equation)

−43x−152+152=20+152(Add 152 to both sides)

−43x=172

−43x

−43

=

172

−43

(Divide both sides by -43)

x=−4

Step: Substitute−4forxiny=5x+19:

y=5x+19

y=(5)(−4)+19

y=−1(Simplify both sides of the equation)

Answer:

x=−4 and y=−1

 

7 0
2 years ago
Develop a probability model for the spinner shown.<br> Will give brainliest!
krok68 [10]

Answer:

Suppose we roll a six-sided number cube. Rolling a number cube is an example of an experiment, or an activity with an observable result. The numbers on the cube are possible results, or outcomes, of this experiment. The set of all possible outcomes of an experiment is called the sample space of the experiment. The sample space for this experiment is \displaystyle \left\{1,2,3,4,5,6\right\}{1,2,3,4,5,6}. An event is any subset of a sample space.

The likelihood of an event is known as probability. The probability of an event \displaystyle pp is a number that always satisfies \displaystyle 0\le p\le 10≤p≤1, where 0 indicates an impossible event and 1 indicates a certain event. A probability model is a mathematical description of an experiment listing all possible outcomes and their associated probabilities. For instance, if there is a 1% chance of winning a raffle and a 99% chance of losing the raffle, a probability model would look much like the table below.

Outcome Probability

Winning the raffle 1%

Losing the raffle 99%

The sum of the probabilities listed in a probability model must equal 1, or 100%.

4 0
3 years ago
I don’t understand how to find the height
ANTONII [103]

Answer:

<u>height</u><u>,</u><u> </u><u>x</u><u> </u><u>is</u><u> </u><u>2</u><u>3</u><u>5</u><u> </u><u>ft</u>

Step-by-step explanation:

From trigonometric ratios:

\cos( \theta)  =  \frac{adjacent}{hypotenuse}

but:

\theta = 90 \degree - 36 \degree \\  \theta = 54 \degree

adjacent is x

hypotenuse is 400 ft

\ \cos ( 54 \degree)  =  \frac{x}{400}  \\  \\ x = 400 \ \cos (54 \degree)  \\ x = 235 \: \:  feet

8 0
3 years ago
Read 2 more answers
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