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3 years ago

May someone please help me with this question

Mathematics

1 answer:

Cloud [144]3 years ago

7 0

Answer:

2+i or 2-i (D)

Step-by-step explanation:

First you use the quadratic formula. X= (-b +/- $\sqrt{b^{2}-4ac }$ )/2a

a=1

b=-4

c=5

X= (4 +/- $\sqrt{16-20}$ )/2

X=(4 +/- $\sqrt{-4}$ )/2

The square root of -4 is 2i. i=√-1. Therefore 2i= 2√-1 .If you simplify that, it becomes √-4i.

X= (4+/- 2i)/2

X= 2+/-i

X= 2+i or 2-i

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Gre4nikov [31]

Given:

$sin\theta=\frac{2\sqrt{3}}{5},\text{ and }\frac{\pi}{2}$

It's required to find cos 2θ.

We use the formula:

$cos(2\theta)=1-2sin^2\theta$

Substituting:

$cos(2\theta)=1-2(\frac{2\sqrt{3}}{5})^2$

Operating:

$\begin{gathered} cos(2\theta)=1-2*\frac{4*3}{25} \\ cos(2\theta)=1-\frac{24}{25} \\ cos(2\theta)=\frac{1}{25} \end{gathered}$

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1 year ago

Solve the equation, and check the solution. w/3 = 0.9 (The w is a variable for the fraction)

zheka24 [161]

Answer:

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Step-by-step explanation:

To solve for what number divided by 3 is equal to 0.9 you can do 0.9*3 and get the answer 2.7. w = 2.7.

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3 years ago

The drama club at Math Academy High School sold tickets to their end of the year play. On Monday they sold 80 tickets for a tota

riadik2000 [5.3K]

Answer: OPTION A

Step-by-step explanation:

Let be "a" the number of adults tickets they sold and "s" the number student of tickets they sold.

With the information given in the exercise you can set up the following System of equations:

$\left \{ {{a+s=80} \atop {6a+4.5s=426}} \right.$

Use the Elimination method to solve the system of equations:

1. Multiply the first equation by -6.

2. Add the equations.

3. Solve for "s" in order to find its value.

Then:

$\left \{ {{-6a+-6s=-480} \atop {6a+4.5s=426}} \right.\\............................\\-1.5s=-54\\\\s=36$

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4 years ago

Please this IXL is due tomorrow I really am struggling.

balandron [24]

Number of people can hold in each car = 10

Solution:

Number of cars in the Blazing Bullet = 6

Total number of people can ride at one time = 60

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Let n be the number of people in each car can hold.

Now write a equation to find the number of people in each car.

Number of cars × number of people in each car = Total number of people

⇒ 6 × n = 60

⇒ 6n = 60

Now, solving this equation.

⇒ 6n = 60

Divide both sides of the equation by 6.

$$ \Rightarrow\frac{6n}{6} = \frac{60}{6}$

$$ \Rightarrow n=10$

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6 0

4 years ago

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Natali [406]

Answer:

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3 years ago

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