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2 years ago

Which is a factor of 5x2 − 15x − 20?

Mathematics

1 answer:

Sholpan [36]2 years ago

7 0

Answer:

x= -1, x=4

Step-by-step explanation:

5x²-15x-20

5x²-20x+5x-20=0

5x(x-4) +5(x-4)

(5x+5) (x-4) =0

5x=-5 or x=4

x= -5/5. or x=4

x= -1 or x=4

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A sample of bacteria is being eradicated by an experimental procedure. The population is following a pattern of exponential deca

77julia77 [94]

Answer:

There will be 50 bacteria remaining after 28 minutes.

Step-by-step explanation:

The exponential decay equation is

$N=N_0e^{-rt}$

N= Number of bacteria after t minutes.

$N_0$ = Initial number of bacteria when t=0.

r= Rate of decay per minute

t= time is in minute.

The sample begins with 500 bacteria and after 11 minutes there are 200 bacteria.

N=200

$N_0$ = 500

t=11 minutes

r=?

$N=N_0e^{-rt}$

$\therefore 200=500e^{-11r}$

$\Rightarrow e^{-11r}=\frac{200}{500}$

Taking ln both sides

$\Rightarrow ln| e^{-11r}|=ln|\frac{2}{5}|$

$\Rightarrow {-11r}=ln|\frac{2}{5}|$

$\Rightarrow r}=\frac{ln|\frac{2}{5}|}{-11}$

To find the time when there will be 50 bacteria remaining, we plug N=50, $N_0$ = 500 and $r}=\frac{ln|\frac{2}{5}|}{-11}$ in exponential decay equation.

$50=500e^{-\frac{ln|\frac25|}{-11}.t}$

$\Rightarrow \frac{50}{500}=e^{\frac{ln|\frac25|}{11}.t}$

Taking ln both sides

$\Rightarrow ln|\frac{50}{500}|=ln|e^{\frac{ln|\frac25|}{11}.t}|$

$\Rightarrow ln|\frac{1}{10}|={\frac{ln|\frac25|}{11}.t}$

$\Rightarrow t= \frac{ln|\frac{1}{10}|}{\frac{ln|\frac25|}{11}.}$

$\Rightarrow t= \frac{11\times ln|\frac{1}{10}|}{{ln|\frac25|}}$

$\Rightarrow t\approx 28$ minutes

There will be 50 bacteria remaining after 28 minutes.

3 0

2 years ago

Loretta’s income last year was $81,300. She made $56,800 at her salaried job and had additional passive income. If Loretta earne

aalyn [17]

Answer:

Option a. $2,040

Step-by-step explanation:

step 1

To find out the amount of the additional passive income last year, subtract the amount earned at her salaried job from Loretta’s income last year

$\$81,300-\$56,800=\$24,500$

step 2

Divide the additional passive income last year by 12 (number of months in a year)

$\$24,500/12=\$2,041.67$

therefore

approximately $2,400 per month

5 0

2 years ago

Read 2 more answers

15 kilograms of rice are separated equally into 4 containers. How many kilograms of rice are in each container? Express your ans

Nadusha1986 [10]

Answer: Fraction= 3 3/4kg

Decimal= 3.75kg

Step-by-step explanation:

15 kilograms of rice are separated equally into 4 containers. To get the number of kilograms of rice are in each container, we divide the total kilograms of rice by the number of containers. This will be:

Kilograms of rice in each container=

15/4 =3 3/4kg as a fraction.

To convert the fraction to decimal, we divide 3 by 4 and add to 3. 3/4 equals 0.75. We then add 3 to 0.75. This will be:

Decimal of 3 3/4 = 3+0.75 = 3.75kg

7 0

2 years ago

Any help would be appreciated!

uranmaximum [27]

i think its contradiction

3 0

2 years ago

Paul is making turkey burgers that are 1/4 pounds each. he has 2.93 pound of turkeys

Vlada [557]

You can make about 11 burgers with that

5 0

2 years ago

Read 2 more answers