What is the quotient? (-3) (-3)2

On a multiple-choice test. Abby randomly guesses on all seven questions. Each question

Murrr4er [49]

Answer:

0.173 probability that she gets exactly three questions correct.

Step-by-step explanation:

For each question, there are only two possible outcomes. Either she guesses the correct answer, or she does not. The probability of guessing the correct answer for a question is independent of other questions. So we use the binomial probability distribution to solve this question.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

In which $C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by the following formula.

$C_{n,x} = \frac{n!}{x!(n-x)!}$

And p is the probability of X happening.

Seven questions:

This means that $n = 7$

Each question has four choices.

Abby guesses, which means that $p = \frac{1}[4} = 0.25$

Find the probability to the nearest thousandth, that Abby gets exactly three questions correct.

This is P(X = 3).

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 3) = C_{7,3}.(0.25)^{3}.(0.75)^{4} = 0.173$

8 0

3 years ago

What is the solution set of the equation? <img src="https://tex.z-dn.net/?f=%5Csqrt%7Bx%7D%20-18%2B9x%3Dx" id="TexFormula1"

bagirrra123 [75]

9514 1404 393

Answer:

x ∈ {2.07014981016}

Step-by-step explanation:

The equation can be rewritten as ...

√x = 18-8x

x = 324 -288x +64x²

64x² -289x +324 = 0

x = (289 ±√577)/128 ≈ {2.07015, 2.44548}

Since √x must be positive, we know that ...

18 -8x ≥ 0

x ≤ 18/8 = 2.25

The larger of the above solutions is extraneous, so the solution set is ...

x ∈ {(289 -√577)/128} ≈ {2.07015}

8 0

2 years ago

What point is on the graph of every direct variation equation

Alexeev081 [22]

Answer: The point (0,0)
This point is also known as the origin

The reason why is because every direct variation equation is of the form y = k*x
where k is some fixed number

If we plugged in x = 0 it leads to y = k*x = k*0 = 0. So (x,y) = (0,0)

4 0

3 years ago

Find x so that the points (x,x+1), (x+2,x+3) and (x+3,2x+4) form a right-angled triangle.

azamat

Let a, b, and c be vectors each starting at the origin and terminating at the points (x, x + 1), (x + 2, x + 3), and (x + 3, 2x + 4), respectively.

Then the vectors a - b, a - c, and b - c are vectors that point in directions parallel to each of the legs formed by the triangle with these points as its vertices.

If this triangle is to contain a right angle, then exactly one of these pairs of vectors must be orthogonal. In other words, one of the following must be true:

(a - b) • (a - c) = 0

or

(a - b) • (b - c) = 0

or

(a - c) • (b - c) = 0

We have

a - b = (x, x + 1) - (x + 2, x + 3) = (-2, -2)

a - c = (x, x + 1) - (x + 3, 2x + 4) = (-3, -x - 3)

b - c = (x + 2, x + 3) - (x + 3, 2x + 4) = (-1, -x - 1)

Case 1: If (a - b) • (a - c) = 0, then

(-2, -2) • (-3, -x - 3) = (-2)×(-3) + (-2)×(-x - 3) = 2x + 12 = 0 ==> x = -6

which would make a - c = (-3, 3) and b - c = (-1, 5), and their dot product is not zero. Then the triangles vertices are at the points (-6, -5), (-4, -3), and (-3, -8).

Case 2: If (a - b) • (b - c) = 0, then

(-2, -2) • (-1, -x - 1) = (-2)×(-1) + (-2)×(-x - 1) = 2x + 4 = 0 ==> x = -2

which would make a - c = (-3, -1) and b = (-1, 1), and their dot product is also not zero. The vertices are the points (-2, -1), (0, 1), and (1, 0).

Case 3: If (a - c) • (b - c) = 0, then

(-3, -x - 3) • (-1, -x - 1) = (-3)×(-1) + (-x - 3)×(-x - 1) = x ² + 4x + 6 = 0

but the solutions to x here are non-real, so we throw out this case.

So there are two possible values of x that make a right triangle, x = -6 and x = -2.

3 0

3 years ago

You can helps me? f(x) = x + 20 g(x) = x + 5 (f o g) (2) = ?

pav-90 [236]

<h2>♪Answer : </h2>

f(x) = x + 20
g(x) = x + 5

»(f o g)(2)

find (f o g)(x)

»f(g(x))

»f(x + 5)

»x + 5 + 20

»x + 25

so, (f o g)(2) is

»2 + 25

»27✅

3 0

2 years ago

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