A freshly inoculated bacterial culture of Streptococcus contains 100 cells. When the culture is checked 60 minutes later, it is determined that there are 450 cells present. Assuming exponential growth, determine the number of cells present at any time t (measured in minutes) and the find the doubling time.​

Step-by-step explanation:

x^2+2x+7y=15

7y=15-x^2-2x

y=15/7-1/7x^2-2/7x , x ∈ all real numbers

Answer:

52.8

Step-by-step explanation:

(3×2.6×2/2)+(3×5×3)

= 7.8+45

= 52.8

Answered by GAUTHMATH

Answer:

[tex]-\frac{x^{2} }{4}[/tex]  -2x - 7

Step-by-step explanation:

Never seen a phone with 3 cameras before or something but ok.

Took a while to use brainly's insert character thingie since fractions and the exponent kinda threw me off.

Answer:

138 yards

Step-by-step explanation:

1 feet is (1/3) yard

414 feet is (1/3)*414=138 yards

Answer:

√65

Step-by-step explanation:

(-6,4) (-5,-4)

√(x2 - x1)² + (y2 - y1)²

√[-5 - (-6)]² + (-4 - 4)²

√(1)² + (-8)²

√1 + 64

√65

9514 1404 393

Answer:

Step-by-step explanation:

The 1-year interest is simply the invested amount times the interest rate.

Let r represent the lower interest rate. Then r+0.02 is the higher rate, and the total interest earned is ...

  1400r + 900(r +.02) = 202

  2300r +18 = 202 . . . . . . . . . .simplify

  2300r = 184 . . . . . . . . . .subtract 18

  r = 184/2300 = 0.08 = 8% . . . . . . divide by the coefficient of r

$1400 was invested at 8%.

$900 was invested at 10%.

Jane is given a $100 gift to start and saves $35 a month from her allowance.

   After 1 month, Jane has saved

   After 2 months, Jane has saved

   After three months, Jane has saved

   and so on

In general, after x months Jane has saved

This means that it makes sense to represent the relationship between the amount saved and the number of months with one constant rate (in this case the constant rate is 35). It makes sense because the amount of money increases by $35 each month. Since the amount of increase is constant, we get constant rate. Also the initial amount is known ($100), so there is a possibility to write the equation of linear function representing this situation.

Step-by-step explanation:

Answer: Solve for the specified variables

Step-by-step explanation:

1. w= A/l

2. d=C/pi

3. s=v-gt

4. y= 5/2x-11/2

5. P^2= P^1V^1 / P^2 Put ^ as lowercase as shown, can't find symbol on my keboard T.T

6. W= Ke2g / V^2

7. h= V / 2/3 pi r^2

8. n=2S/a+k

9. S=A/pi r - r (not 100% sure on that one)

10. r= E/I-R

11. h= E-1/2mv^2/mg

12. a=K+5b/b+3

13. c=ab/b+a

Wooh, finally finished all that. Hope I didn't make any mistakes. Have a great day!

Answer:

1. The discount is 10%

2. 250

Answer:

undefined, invalid

and for a limit expression like a/x, x->0 we also say this is infinite.

270 degrees is at the bottom of the unit circle, and it splits the 3rd and 4th quadrants.

Its terminal point is (0, -1).

Hope this helps!

Answer:

A. (0, -1)

Step-by-step explanation:

This question requires a chart to answer. The chart is inserted in the answer.

270 degrees is all the way at the bottom, at South which shows that 270 degrees is at (0, -1).

Meaning, the answer is A, (0, -1).

Hope this helped.

Answer:

Step-by-step explanation:

[tex]\tt{ \green{P} \orange{s} \red{y} \blue{x} \pink{c} \purple{h} \green{i} e}[/tex]

Answer:

50

Step-by-step explanation:

So we know that 42/3=14.

3 years before was:

14-3=11

42-3=39

The sum of 11+39 is 50

Answer:

y = 3x - 5

Step-by-step explanation:

Slope = 3

x-intercept (what the value of y is when its 0) = -5 so y = 3x - 5

Answer:

y = 3x - 5

Step-by-step explanation:

Find the slope of the line between (0,−5)(0,-5) and (3,4)(3,4) using m=y2−y1x2−x1m=y2-y1x2-x1, which is the change of yy over the change of xx.

m=3m=3

Use the slope 33 and a given point (0,−5)(0,-5) to substitute for x1x1 and y1y1 in the point-slope form y−y1=m(x−x1)y-y1=m(x-x1), which is derived from the slope equation m=y2−y1x2−x1m=y2-y1x2-x1.

y−(−5)=3⋅(x−(0))y-(-5)=3⋅(x-(0))

Simplify the equation and keep it in point-slope form.

y+5=3⋅(x+0)

Add xx and 00.

y+5=3xy+5=3x

Subtract 55 from both sides of the equation.

y=3x−5

Answer:

82

Step-by-step explanation:

1/3( x+9/7) + 3^4

Let x = 12/7

1/3( 12/7+9/7) + 3^4

PEMDAS says parentheses first

1/3( 21/7) + 3^4

1/3(3) +3^4

Then exponents

1/3(3)+81

Then multiply

1+81

82

Answer:

The critical value used is [tex]T_c = 2.132[/tex]

The 90% confidence interval for the average net change in a student's score after completing the course is (14.357, 22.843).

Step-by-step explanation:

Before building the confidence interval, we need to find the sample mean and the sample standard deviation.

Sample mean:

[tex]\overline{x} = \frac{16+21+22+12+22}{5} = 18.6[/tex]

Sample standard deviation:

[tex]s = \sqrt{\frac{(16-18.6)^2+(21-18.6)^2+(22-18.6)^2+(12-18.6)^2+(22-18.6)^2}{4}} = 4.45[/tex]

Confidence interval:

We have the standard deviation for the sample, so the t-distribution is used to solve this question.

The first step to solve this problem is finding how many degrees of freedom,which is the sample size subtracted by 1. So

df = 5 - 1 = 4

90% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 4 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.9}{2} = 0.95[/tex]. So we have T = 2.132. The critical value used is [tex]T_c = 2.132[/tex]

The margin of error is:

[tex]M = T\frac{s}{\sqrt{n}} = 2.132\frac{4.45}{\sqrt{5}} = 4.243[/tex]

In which s is the standard deviation of the sample and n is the size of the sample.

The lower end of the interval is the sample mean subtracted by M. So it is 18.6 - 4.243 = 14.357

The upper end of the interval is the sample mean added to M. So it is 18.6 + 4.243 = 22.843.

The 90% confidence interval for the average net change in a student's score after completing the course is (14.357, 22.843).

Answer:

B

Step-by-step explanation:

1) I think 15 choose (d)

2) The choose (C) -4fg+4g

3) The choose (d) 3xy/2

4) The choose (a) ab/6

5) The choose (C) 2p+4q-6

6)

[tex]\pi {r}^{2} h = 3.14 \times {3}^{2} \times 1.5 = 42.39 {m}^{3} = 42.390 {m}^{3} [/tex]

Point 6 I think there is an error because the unit m must be m³ because it is r² (m²) and h(m) becomes m³.

I hope I helped you^_^

Answer:

B. x = 2.77

Step-by-step explanation:

3^x = 21

You first look for a base for 21 that is 3 to the power of something.

21 = 3^2.77

So 3^x = 2^2.77

They have the same base so

x= 2.77

Answer:

90 ml of the 25 percent mixture and 585 of pure alcohol

Step-by-step explanation:

Firstly, you should find the quantity of alcohol in the desired mixture.

675:100*90= 675*0.9= 607.5

Firstly,  define all the 25 percents mixure as x, the pure alcohol weight is y.

1. x+y= 675 (because the first and the second liquid form a desired liquid).

Then find the equation for spirit

The first mixture contains 25 percents. It is x/100*25= 0.25x

When the second one consists of pure alcohol, it contains 100 percents of spirit,  so it is x.

2. 0.25x+y=607.5

Then you have a system of equations ( 1.x+y= 675 and 2. 0.25x+y= 607.5)

try 2-1 to get rid of y

x+y- (0.25x+y)= 675-607.5

0.75x= 67.5

x= 90

y= 675-x= 675-90= 585

It means that you need90 ml of the 25percents mixture and 585 0f pure alcohol

Answer:

y > -1/2 x + 4

Step-by-step explanation:

Equation of a line : (y-y1)/(y2-y1) = (x-x1)/(x2-x1)

(y-4)/(2-4)= (x-0)/(4-0)

(y-4)/-2 = x/4

(-y+4)/2 = x/4

-y+4 = 1/2 x

-y = 1/2 x - 4

y = -1/2 x + 4

the solutions of the inequality are the points above this line, so

y > -1/2 x + 4

Answer:

x = 45

Step-by-step explanation:

5 (2x - 5) = 1/2 (18x + 40)​

10x - 25 = 9x + 20

10x = 9x + 45

x = 45

please mark this answer as brainlist

Answer:

12x - 28° = 116°

7x + 32° = 116°

Step-by-step explanation:

12x - 28° and 7x + 32° are vertical angles. Vertical angles are congruent.

Therefore, to find the measure of each angle, we have to set each equation equal to each other as follows:

12x - 28° = 7x + 32°

Collect like terms

12x - 7x = 28 + 32

5x = 60

Divide both sides by 5

5x/5 = 60/5

x = 12

✔️12x - 28°

Plug in the value of x

12(12) - 28

= 144 - 28

= 116°

✔️7x + 32°

7(12) + 32

= 84 + 32

= 116°

[tex]\\ \sf\longmapsto \left\{x|x \epsilon I,x\leqslant 3\right\}[/tex]

In listing

[tex]\\ \sf\longmapsto \left\{\dots,0,1,2,3\right\}[/tex]

9514 1404 393

Answer:

  20th

Step-by-step explanation:

The person will receive all gifts if the are all of a multiple of 2, a multiple of 4, and a multiple of 5. Since 4 is already a multiple of 2, the person who will receive all is the one who is a multiple of 4 and 5.

20 is 4×5, so is a multiple of both numbers. There is no smaller number that is a multiple of both 4 and 5.

The 20th person will receive all gifts.

_____

The value we have determined here is called the "least common multiple" (LCM). It is the product of the unique prime factors of the numbers of interest, raised to the highest power that appears in any of the numbers.

  2 = 2¹

  4 = 2²

  5 = 5¹

LCM(2, 4 5) = 2² × 5¹ = 20

Answer:

[tex]\frac{a+3}{6}[/tex]

Step-by-step explanation:

Treat it like any other math problem with a equals sign:

6x + 3 = a

subtract 3 from both sides: 6x = a + 3

divide both sides by 6: [tex]x = \frac{a+3}{6}[/tex]

swap the ≥ back in: [tex]x \geq \frac{a+3}{6}[/tex]

the only time the sign flips is if you divide by a negative

Answer:

X-4x+11=8

-3x+12-8=0

-3x+4=0

3x=4

X=4/3

Answer:

x = 4/3 or 1.3

Step-by-step explanation:

Combine like terms

8 = -3x + 12

Move the terms

3x = 12 - 8

Calculate

3x = 4

Divide both sides by 3

x = 4/3

or

x = 1.3