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Anon25 [30]
3 years ago
9

Please help, and thank you!

Mathematics
1 answer:
lawyer [7]3 years ago
8 0

Answer:

3. C

4. D

Step-by-step explanation:

3.

x^2+25=0\\x^2=-25\\x=\pm\sqrt{-25}

Once \sqrt{-1}=i

x=\pm5i

4.

A quadratic equation has no real roots when the discriminant (\Delta) is negative. \Delta.

Let's try all the equations:

(A)

2x^2-7x-9=0\\\\\Delta=\sqrt{\left(-7\right)^2-4\cdot \:2\left(-9\right)}\\\Delta=\sqrt{\left(-7\right)^2+4\cdot \:2\cdot \:9}\\\Delta=\sqrt{121} \\\Delta=11

(B)

2x^2=7x\\2x^2-7x=0\\x(2x-7)=0\\x=0\\\text{or}\\2x-7=0\\2x=7\\\\

$x=\frac{7}{2} $

(C)

2x^2+7x-9=0\\\Delta = \sqrt{7^2-4\cdot \:2\left(-9\right)}\\\Delta = \sqrt{7^2+4\cdot \:2\cdot \:9}\\\Delta = \sqrt{121} \\\Delta= 11

(D)

2x^2-7x+9=0\\\Delta = \sqrt{\left(-7\right)^2-4\cdot \:2\cdot \:9}\\\\\Delta=\sqrt{-23} \\\Delta=\sqrt{23i}

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Your round-trip drive to school is 3710 miles. How many miles do you drive to and from school in 5 days?
Anit [1.1K]

Answer:

Read below.

Step-by-step explanation:

If you include going back home, then its

3710 miles × 5 days =

<u>18,550 miles</u>

If you don't include going back home, then it's

3710 miles ÷ 2 × 5 days =

1855 miles × 5 days =

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6 0
3 years ago
Suponhamos que temos x casos confirmados de coronavírus e y casos suspeitos. A - Se triplicar os casos confirmados e cair a meta
aleksandr82 [10.1K]

Answer:

[3x + (y/2)]

Step-by-step explanation:

English Translation

Suppose we have x confirmed cases of coronavirus and y suspected cases. A - If the confirmed cases triple and half of the suspects fall, we will have the following expression to represent the total number of cases:

Solution

Number of confirmed cases = x

Number of suspected cases = y

Number of confirmed cases triples and becomes 3x

Half of the suspected cases fall and becomes (y/2)

Total number of cases then becomes

[3x + (y/2)]

In Portugese/Em português

Número de casos confirmados = x

Número de casos suspeitos = y

O número de casos confirmados triplica e se torna 3x

Metade dos casos suspeitos cai e se torna (y / 2)

O número total de casos passa a ser

[3x + (y / 2)]

Hope this Helps!!!

Espero que isto ajude!!!

8 0
3 years ago
Can someone explain how to do this?
pogonyaev

Answer:

For the first one use the formula

y=x*2

For the second use

y=x*4

The third is

y=x*15

The fourth is

y=x*16

Step-by-step explanation:

To find the value of the y units, u have to multiply any x unit with the first y unit given but not 0

idk if it makes sense but i tried

good luck!!

7 0
3 years ago
Read 2 more answers
​ y=−2x−5 y=2x−2 ​
Anettt [7]

Answer:

work is shown and pictured

7 0
3 years ago
Write an expression for the sequence of operations described below. multiply 3 by t, triple the result, then raise what you have
Nadusha1986 [10]

Answer: 43046721(t^8)

Step-by-step explanation:

So first, multiply 3 by t to get 3t. Then, multiply it again by 3 to get 9t. Raise it to the 8th power to get (9^8)(t^8). This gives you 43046721(t^8)

4 0
3 years ago
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