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3 years ago

7

Iodine-131 is a radioactive material with half-life of eight days. A scientist starts with 100 grams of iodinie- 131. Which func

tion can be used to estimate the number of grams of iodine-131 remaining at the end of x days?
A. f(x)= 100(0.92)^x

B. f(x)= 100 (1.09)^x

C. f(x)= (0.92)^x

D. f(x)= (1.090^x

2 answers:

Viktor [21]3 years ago

7 0

Answer:

poop

Step-by-step explanation:

poop

MrRissso [65]3 years ago

6 0

The correct answer is Choice A.

This is an example of an exponential equation, so we need the formula $y=ab^x$ .

The a value is the starting value of 100. The b value must be a decimal lower than 1 because it is decreases.

If you substitute in 8 for x, you will see that the output is about 50 (half of 100).

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2 - X<-7 (x > 9)<br><br>solve and graph<br>

NARA [144]

Use Photomath it graphs too

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4 years ago

Drag the tiles to the correct boxes to complete the pairs not all tiles will be used match each quadratic graph to its respectiv

ch4aika [34]

Answer:

Part 1) The function of the First graph is $f(x)=(x-3)(x+1)$

Part 2) The function of the Second graph is $f(x)=-2(x-1)(x+3)$

Part 3) The function of the Third graph is $f(x)=0.5(x-6)(x+2)$

See the attached figure

Step-by-step explanation:

we know that

The quadratic equation in factored form is equal to

$f(x)=a(x-c)(x-d)$

where

a is the leading coefficient

c and d are the roots or zeros of the function

Part 1) First graph

we know that

The solutions or zeros of the first graph are

x=-1 and x=3

The parabola open up, so the leading coefficient a is positive

The function is equal to

$f(x)=a(x-3)(x+1)$

Find the value of the coefficient a

The vertex is equal to the point (1,-4)

substitute and solve for a

$-4=a(1-3)(1+1)$

$-4=a(-2)(2)$

$a=1$

therefore

The function is equal to

$f(x)=(x-3)(x+1)$

Part 2) Second graph

we know that

The solutions or zeros of the first graph are

x=-3 and x=1

The parabola open down, so the leading coefficient a is negative

The function is equal to

$f(x)=a(x-1)(x+3)$

Find the value of the coefficient a

The vertex is equal to the point (-1,8)

substitute and solve for a

$8=a(-1-1)(-1+3)$

$8=a(-2)(2)$

$a=-2$

therefore

The function is equal to

$f(x)=-2(x-1)(x+3)$

Part 3) Third graph

we know that

The solutions or zeros of the first graph are

x=-2 and x=6

The parabola open up, so the leading coefficient a is positive

The function is equal to

$f(x)=a(x-6)(x+2)$

Find the value of the coefficient a

The vertex is equal to the point (2,-8)

substitute and solve for a

$-8=a(2-6)(2+2)$

$-8=a(-4)(4)$

$a=0.5$

therefore

The function is equal to

$f(x)=0.5(x-6)(x+2)$

3 0

4 years ago

you pick a card at random without getting the first card back you pick a second card at random what is the probability of pickin

Keith_Richards [23]

We have to calculate the probability of picking a 4 and then a 5 without replacement.

We can express this as the product of the probabilities of two events:

• The probability of picking a 4

,

• The probability of picking a 5, given that a 4 has been retired from the deck.

We have one card in the deck out of fouor cards that is a "4".

Then, the probability of picking a "4" will be:

$P(4)=\frac{1}{4}$

The probability of picking a "5" will be now equal to one card (the number of 5's in the deck) divided by the number of remaining cards (3 cards):

$P(5|4)=\frac{1}{3}$

We then calculate the probabilities of this two events happening in sequence as:

$\begin{gathered} P(4,5)=P(4)\cdot P(5|4) \\ P(4,5)=\frac{1}{4}\cdot\frac{1}{3}=\frac{1}{12} \end{gathered}$

Answer: 1/12

8 0

1 year ago

A van travels from Town A to Town B. It uses 1 gallon of gas for every 24 miles traveled. A) How many gallons of gas does the va

Setler79 [48]

Answer:

A) $\frac{x}{8}$ gallons

B) Distance between Town A and Town B is $48y$ miles

Step-by-step explanation:

A)

We know, number of gallons = $\frac{DistanceTravelled}{MilesPerGallon}$

if miles per gallon (mpg) is given as 24 & total distance travelled is 3x miles, then, using formula we have:

Number of Gallons = $\frac{DistanceTravelled}{MilesPerGallon}=\frac{3x}{24}=\frac{x}{8}$

B)

Now, given is number of gallons = 2y & we know mpg is 24; <em>so what is the distance?</em>

We use the same formula and solve for distance (let distance between A and B be "D"):

$NumberOfGallons=\frac{DistanceTravelled}{MilesPerGallon}\\2y=\frac{D}{24}\\D=2y*24\\D=48y$

7 0

3 years ago

How do i Solve: 3x2−6x−12=0 ?

MrMuchimi

Answer:

1 + root 5, 1 - root 5

Step-by-step explanation:

I assume you mean 3x^2-6x-12=0.

First, note that you can divide both sides by 3. You get:

x^2-2x-4=0

Use the quadratic equation.

$x=\frac{2\pm\sqrt{4+16}}{2}=\frac{2\pm2\sqrt{5}}{2}=1\pm\sqrt{5}$

Therefore, x=1 + root 5, 1 - root 5

4 0

3 years ago