What is the correct letter name for Ð1 below?<br><br>

In 8 months, 55.6 gallons were used. Find the unit rate.

OLga [1]

6.95 gallons in 1 month

8 0

2 years ago

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Which is a solution to the equation?<br> (х-2)(х + 5) = 18?

jok3333 [9.3K]

$\bf (x-2)(x+5)=18\implies \stackrel{\mathbb{F~O~I~L}}{x^2+3x-10}=18\implies x^2+3x-28=0 \\\\\\ (x-4)(x+7)=0\implies x= \begin{cases} 4\\ -7 \end{cases}$

4 0

2 years ago

A mailbox that is 36 inches tall is beside a tree.The length of the mailboxes shadow is 28 inches.The length of the trees shadow

mixer [17]

Answer:

10.5 feet

Step-by-step explanation:

In this problem, we have two similar triangles:

- One consists of the mailbox, its shadow and the hypothenuse

- The other one consists of the tree, its shadow and the hypothenuse

The two triangles are similar, so they have same proportions between their sides: therefore, we can apply the rule of three:

$\frac{m}{s_m}=\frac{t}{s_t}$

where

m = 36 in is the height of the mailbox

$s_m=28 in$ is the shadow of the mailbox

t is the height of the tree

$s_t=98 in$ is the length of the shadow of the tree

Solving for t, we find the height of the tree:

$t=\frac{m\cdot s_t}{s_m}=\frac{(36)(98)}{28}=126 in$

And since

1 feet = 12 inches

The height of the tree in feet is

$t=\frac{126}{12}=10.5 ft$

3 0

3 years ago

Find the roots of the equation x^2+2x+5=0

stiv31 [10]

Answer:

x = - 1 ± 2i

Step-by-step explanation:

we can use the discriminant b² - 4ac to determine the nature of the roots

• If b² - 4ac > , roots are real and distinct

• If b² - 4ac = 0, roots are real and equal

• If b² - ac < 0, roots are not real

for x² + 2x + 5 = 0

with a = 1, b = 2 and c = 5, then

b² - 4ac = 2² - (4 × 1 × 5 ) = 4 - 20 = - 16

since b² - 4ac < 0 there are 2 complex roots

using the quadratic formula to calculate the roots

x = ( - 2 ± $\sqrt{-16}$ ) / 2

= (- 2 ± 4i ) / 2 = - 1 ± 2i

7 0

3 years ago

In a recent telephone survey, 5,000 randomly selected teenagers were asked to cite their primary social network sites. Six of 10

aleksklad [387]

Answer:

b. There is a 95% chance that the true proportion of teenagers who use Mybook as their primary social network site is in the interval (0.2964, 0.9036).

Step-by-step explanation:

Hello!

In general, a 95% confidence interval for the population proportion can be interpreted as: There is a 95% chance (or confidence) that the interval will contain the true value of the proportion.

(Remember the confidence level of 95% means that if you were to make 100 intervals for the population proportion, 95 of them will contain its true value)

The estimated parameter is the population proportion of teenagers that use Mybook as their primary social network site.

With this in mind then you can say that there is a 95% probability that the interval (0.2964, 0.9036) will contain the true value of the proportion of teenagers that use Mybook as their primary social network site.

The correct answer is: b

I hope this helps!

8 0

2 years ago

What is the correct letter name for Ð1 below?￼

What is the correct letter name for Ð1 below?