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4 years ago

Solve 4r2 – 9 = 91. A:{±3} B:{±4} C:{±5} D:{±6}

Mathematics

2 answers:

fomenos4 years ago

6 0

4r² - 9 = 91
4r² = 91 + 9
4r² = 100
r² = 25
r = + / - 5

Correct option C

miskamm [114]4 years ago

4 0

Take the root of both sides and solve. The answer is C.

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Solve 3(2x-5)-4x+8=-1

777dan777 [17]

Answer:

Step-by-step explanation:

Step 1:

3 ( 2x - 5 ) - 4x + 8 = - 1

Step 2:

5x - 15 - 4x + 8 = - 1

Step 3:

x - 15 + 8 = - 1

Step 4:

x - 7 = - 1

Answer:

x = 6

Hope This Helps :)

7 0

3 years ago

What is the value of the discriminant? 4x2+15x=3x-9

Ray Of Light [21]

Answer:

Step-by-step explanation:

Use the values of a , b , and c to find the discriminant.

8 0

3 years ago

What is the measure of angle C

Alexxandr [17]

You need to learn no to copy it kiddo

8 0

3 years ago

Read 2 more answers

The manager wants to advertise that anybody who isn't served within a certain number of minutes gets a free hamburger. But she d

aksik [14]

Answer:

The number of minutes advertisement should use is found.

x ≅ 12 mins

Step-by-step explanation:

(MISSING PART OF THE QUESTION: AVERAGE WAITING TIME = 2.5 MINUTES)

For such problems, we can use probability density function, in which probability is found out by taking integral of a function across an interval.

Probability Density Function is given by:

$f(t)=\left \{ {{0 ,\-t$

Consider the second function:

$f(t)=\frac{e^{-t/\mu}}{\mu}\\$

Where Average waiting time = μ = 2.5

The function f(t) becomes

$f(t)=0.4e^{-0.4t}$

The manager wants to give free hamburgers to only 1% of her costumers, which means that probability of a costumer getting a free hamburger is 0.01

The probability that a costumer has to wait for more than x minutes is:

$\int\limits^\infty_x {f(t)} \, dt= \int\limits^\infty_x {}0.4e^{-0.4t}dt$

which is equal to 0.01

Solve the equation for x

$\int\limits^{\infty}_x {0.4e^{-0.4t}} \, dt =0.01\\\\\frac{0.4e^{-0.4t}}{-0.4}=0.01\\\\-e^{-0.4t} |^\infty_x =0.01\\\\e^{-0.4x}=0.01$

Take natural log on both sides

$ln (e^{-0.4x})=ln(0.01)\\-0.4x=ln(0.01)\\-0.4x=-4.61\\x= 11.53$

<h3>Results</h3>

The costumer has to wait x = 11.53 mins ≅ 12 mins to get a free hamburger

3 0

3 years ago

When 24 is subtracted from a number and that difference is multiplied by 1/4, the result is 4.

Katen [24]

If (x-24)0.25 = 4, distribute 0.25 within the parenthesis.
0.25x - 6 = 4
0.25x = 10
Divide both sides by 0.25
x = 40

8 0

3 years ago