Need help pick 3 right answers .?

Find the discriminant, and determine the number of real solutions. then solve x^2 +8x+20=0

vodomira [7]

Answer:

Part 1) The quadratic equation has zero real solutions

Part 2) The solutions are

$x_1=-4+2i$ and $x_2=-4-2i$

Step-by-step explanation:

we know that

The formula to solve a quadratic equation of the form $ax^{2} +bx+c=0$ is equal to

$x=\frac{-b(+/-)\sqrt{b^{2}-4ac}} {2a}$

in this problem we have

$x^{2}+8x+20=0$

so

$a=1\\b=8\\c=20$

The discriminant is equal to

$D=(b^{2}-4ac)$

If D=0 -----> the quadratic equation has only one real solution

If D>0 -----> the quadratic equation has two real solutions

If D<0 -----> the quadratic equation has two complex solutions

<em>Find the value of D</em>

$D=8^{2}-4(1)(20)=-16$ -----> the quadratic equation has two complex solutions

<em>Find out the solutions</em>

substitute the values of a,b and c in the formula

$x=\frac{-8(+/-)\sqrt{8^{2}-4(1)(20)}} {2(1)}$

$x=\frac{-8(+/-)\sqrt{-16}} {2}$

Remember that

$i=\sqrt{-1}$

$x=\frac{-8(+/-)4i} {2}$

$x_1=\frac{-8(+)4i} {2}=-4+2i$

$x_2=\frac{-8(-)4i} {2}=-4-2i$

8 0

4 years ago

A turtle is on a rock that is 1.1 feet above sea level. The turtle dives under water. The turtle's total change in altitude duri

ss7ja [257]

Answer:

1.1-5.4=4.3

Step-by-step explanation:

because the total is 5.4 and the turtle was 1.1 up so subtract to see how much the turtle sank to the Bottom

6 0

2 years ago

Luna mixes 3/4 cup of orange juice with 3/8 cup of cranberry juice. She gives 5/8 cup of juice to mags. How much is left in luna

Debora [2.8K]

Answer:

The answer is 1/2

Step-by-step explanation:

First you must the least common denominator so that you can add the two fractions. The least common denominator between 3/4 and 3/8, would be 8.

To get 3/4 to the least common denominator, you have to multiply top and bottom by 2. The product of this will be 6/8.

Next you add the two fractions: 6/8 + 3/8 = 9/8

Simplify your improper fraction to get on and 1 eighths or in number form 1 1/8

After this you must subtract how much she gave away so you can use your improper fraction to make it easier and subtract five eighths from nine eighths: 9/8 - 5/8 = 4/8

So, Luna has four eighths of a glass left but first you must simplify your answer. both 4 and 8 divide by 4 to get 1/2.

So Luna's glass only has 1/2 in the cup.

Make sure you be optimistic and see it as half full, instead of the pessimistic view of half empty. Remember to stay positive and share good vibes. Hope this answer helps you.

4 0

3 years ago

An online test of English spelling looked at how well people spelled difficult words. The bar graph to the right shows how many

sweet-ann [11.9K]

Answer:

60 ; 5220

Step-by-step explanation:

A) From the horizontal bar chart provided, it could be inferred that 85 people spell the word 'weird' correctly. The graph is scaled on a fixed interval of 10. Hence, the midpoint of 10 = 5

(80 + 5) = 85

B) In a group consisting of 8719 randomly selected people estimate how many more people can correctly spell weird than inoculate

From the graph :

85 per 100 could spell weird correctly while,

About 25 per 100 could spell inoculate correctly.

Difference In number per 100 people

(85 - 25) = 60 people per 100

We could round 8719 to the nearest 100 = 8700

Number of 100's in 8700 = 8700/100 = 87

(87 × 60) = 5,220 people

4 0

3 years ago

The owners of an eyeglass store claim that they fill customers' orders, on average, in 60 minutes with a standard deviation of 1

melomori [17]

By applying z-score formula we got that if a reporter determines a mean order time of 63 minutes then value o Z is 1.19

<h3>What is standard deviation?</h3>

Standard deviation is a number used to tell how measurements for a group are spread out from the average (mean), or expected value

Here given that

The owners of an eyeglass store claim that they fill customers' orders, on average, in 60 minutes with a standard deviation of 15. 9 minutes. Based on a random sample of 40 orders, a reporter determines a mean order time of 63 minutes

mean=μ=60

standard deviation=σ=15.9

number of sample=n=40

$\bar{x}=63 \\$

Now we can calculate z by z-score formula as

$z=\frac{\bar{x}-\mu}{\frac{\sigma}{\sqrt{n}}} \\\\&=\frac{63-60}{\frac{15 \cdot 9}{40}} \\ \\=\frac{3}{2.5140} \\ \\=1.19\end{aligned}$

By applying z-score formula we got that if a reporter determines a mean order time of 63 minutes then value o Z is 1.19

To learn more about standard deviation visit :brainly.com/question/12402189

5 0

2 years ago