Learn with an example

What is the value of f(x) when x = -3?

Gemiola [76]

Answer:

C) 16

Step-by-step explanation:

f(x)=2x^2+4x+10

Let x = -3

f(-3) = 2(-3)^2 +4(-3) +10

= 2(9)- 12+10

= 18 -2

= 16

6 0

4 years ago

Can someone please help me?!

Alex777 [14]

Answer:

3.5/14
2.5/10
3/12
See the attached solution

3 0

3 years ago

For what values of x does the function y=2x+13 take on a positive value? a negative value?

arlik [135]

Hello,

The answer is x= y-13 / 2 ( everything after the x= is a fraction)

How to solve;

Start by subtracting 13 from both sides of y=2x+13, we do this to get the x on 1 side

So now we have y-13=2x

Next divide both sides by 2, we do this to get x by it self.

y-13/2=x

Now we flip the problem and there you have it!

Edit: The x does not have a Pos or neg value, The only way to know what x is, is to solve for x.

3 0

3 years ago

An apartment building has 35 floors with 12 apartments on each floor. There are 300 apartments that have 2 bedrooms. The rest of

Lena [83]

Answer:

120 is the answer, if we multiply 35×12= 420 apartments and there is 300 with 2 bedrooms. 420-300= 120 apartments with 1 bedroom. I hope it was helpful!

4 0

3 years ago

Qualification exams for becoming a state-certified welding inspector are based on multiple-choice tests. As in any multiple-choi

erik [133]

Answer:

(a) The probability distribution of the random variable X is Binomial.

(b) The mean and standard deviation of the 25-question test are 5 and 2 respectively.

(c) The value of x is 0.34.

Step-by-step explanation:

The random variable X is defined as the number of correct answers given by a person who is guessing each answer on a 25-question exam.

There are five possible answer for every question.

This implies that the probability of getting a correct answer is:

P (X) = 0.20.

There are a total of n = 25 questions.

Every answer is independent of the others.

(a)

The random variable X has finite number of independent trials (i.e. 25 questions). There are only two outcomes for each trial, i.e. Success = correct answer and Failure = wrong answer. Each trial has the same probability of success (, i.e. P (X) = 0.25).

Thus, the probability distribution of the random variable X is Binomial with parameters n = 25 and p = 0.20.

(b)

Compute the mean of the random variable X as follows:

$E(X)=np\\=25\times 0.20\\=5$

Compute the standard deviation of the random variable X as follows:

$SD(X)=\sqrt{np(1-p)}\\=\sqrt{25\times 0.20\times (1-0.20)}\\=2$

Thus, the mean and standard deviation of the 25-question test are 5 and 2 respectively.

(c)

The sample is large and the probability of success is close to 0.50.

So a Normal approximation to binomial can be applied to approximate the distribution of X if the following conditions are satisfied:

1. np ≥ 5

2. n(1 - p) ≥ 5

Check the conditions as follows:

$np=25\times 0.20=5=5\\\\n(1-p)=25\times (1-0.20)=20>5$

Thus, a Normal approximation to binomial can be applied.

So, $X\sim N(5, 2^{2})$

It is provided that the minimum passing score foe the test is such that only 1% of students who are guessing will pass the test.

That is P (X < x) = 0.01.

⇒ P (Z < z) = 0.01

The value of z is -2.33.

Compute the value of x as follows:

$z=\frac{x-\mu}{\sigma}\\\\-2.33=\frac{x-5}{2}\\\\x=5-(2.33\times 2)\\\\x=0.34$

Thus, the value of x is 0.34.

4 0

4 years ago