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2 years ago

Use the discriminant to describe the roots of each equation. Then select the best description.

1 answer:

7 0

The quadratic equation 3 · x² + 7 · x - 2 = 0 has a positive discriminant. Thus, the expression has two distinct real roots (real and irrational roots).

<h3>How to determine the characteristics of the roots of a quadratic equation by discriminant</h3>

Herein we have a quadratic equation of the form a · x² + b · x + c = 0, whose discriminant is:

d = b² - 4 · a · c (1)

There are three possibilities:

d < 0 - conjugated complex roots.
d = 0 - equal real roots (real and rational root).
d > 0 - different real roots (real and irrational root).

If we know that a = 3, b = 7 and c = - 2, then the discriminant is:

d = 7² - 4 · (3) · (- 2)

d = 49 + 24

d = 73

To learn more on quadratic equations: brainly.com/question/2263981

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Twenty percent of drivers driving between 10 pm and 3 am are drunken drivers. In a random sample of 12 drivers driving between 1

Lesechka [4]

Answer:

(a) 0.28347

(b) 0.36909

(d) 0.9806

Step-by-step explanation:

Given information:

n=12

p = 20% = 0.2

q = 1-p = 1-0.2 = 0.8

Binomial formula:

$P(x=r)=^nC_rp^rq^{n-r}$

(a) Exactly two will be drunken drivers.

$P(x=2)=^{12}C_{2}(0.2)^{2}(0.8)^{12-2}$

$P(x=2)=66(0.2)^{2}(0.8)^{10}$

$P(x=2)=\approx 0.28347$

Therefore, the probability that exactly two will be drunken drivers is 0.28347.

(b)Three or four will be drunken drivers.

$P(x=3\text{ or }x=4)=P(x=3)\cup P(x=4)$

$P(x=3\text{ or }x=4)=P(x=3)+P(x=4)$

Using binomial we get

$P(x=3\text{ or }x=4)=^{12}C_{3}(0.2)^{3}(0.8)^{12-3}+^{12}C_{4}(0.2)^{4}(0.8)^{12-4}$

$P(x=3\text{ or }x=4)=0.236223+0.132876$

$P(x=3\text{ or }x=4)\approx 0.369099$

Therefore, the probability that three or four will be drunken drivers is 0.3691.

(c)

At least 7 will be drunken drivers.

$P(x\geq 7)=1-P(x$

$P(x\leq 7)=1-[P(x=0)+P(x=1)+P(x=2)+P(x=3)+P(x=4)+P(x=5)+P(x=6)]$

$P(x\leq 7)=1-[0.06872+0.20616+0.28347+0.23622+0.13288+0.05315+0.0155]$

$P(x\leq 7)=1-[0.9961]$

$P(x\leq 7)=0.0039$

Therefore, the probability of at least 7 will be drunken drivers is 0.0039.

(d) At most 5 will be drunken drivers.

$P(x\leq 5)=P(x=0)+P(x=1)+P(x=2)+P(x=3)+P(x=4)+P(x=5)$

$P(x\leq 5)=0.06872+0.20616+0.28347+0.23622+0.13288+0.05315$

$P(x\leq 5)=0.9806$

Therefore, the probability of at most 5 will be drunken drivers is 0.9806.

5 0

3 years ago

If g(x) = 4√x-8 , which statement is true?

Mariana [72]

We have the following function:

$g(x)=4\sqrt{x}-8$

So if we graph this function we will get the Figure below. Thus, let's study both the equation and the graph to get some conclusions. Therefore, we can assure these statements:

First. The function is defined only for $x\geq 0$ as shown in the Figure. This is also true because of $\sqrt{x}$ where $x$ must be greater (or equal) than zero.

Second. The range of the function are the values of $y\geq -8$ .

Third. If $x$ creases then $y$ always creases, too.

4 0

3 years ago

Read 2 more answers

The lengths of the sides of a triangle are represented by 3 consecutive even integers. if the perimeter of the triangle is 72 fe

iris [78.8K]

P = a + b + c
P = 72
a = x
b = x + 2
c = x + 4

72 = x + x + 2 + x + 4
72 = 3x + 6
72 - 6 = 3x
66 = 3x
66/3 = x
22 = x

x + 2 = 22 + 2 = 24
x + 4 = 22 + 4 = 26

the sides of ur triangle are : 22,24,26 <==

6 0

2 years ago

Please help due ASAP Show workings please

Nostrana [21]

Step-by-step explanation:

I don't know if this is the right way to so it, but I would do it like this

since a triangle has 180 degrees, the angles all have to add up to 180

So 180 = a + b + c

we already know a, its 95

So 180 = 95 + b + c

now we know the equation for b, so we'll just put it there instead of the b, and since the angles are the same, we should put it instead of c too

180 = 95 + (4x-15) + (4x-15)

now subtract 95 from both sides

85 = (4x-15) + (4x-15)

add the xs and numbers together

85 = 8x - 30

now add the 30 to both sides

115 = 8x

divide by 8

your x is 14 3/8 or 14.375 or 115/8

that's not your angle, that's your x

5 0

3 years ago

Find the area of the shaded region in the polygon below.

mezya [45]

Answer:

Step-by-step explanation:

I multiply 3 and 7 that give 35

8 0

2 years ago

Read 2 more answers