1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
monitta
3 years ago
12

Show me how to get an answer for: 1a + 18 = 7a

Mathematics
2 answers:
nekit [7.7K]3 years ago
3 0
1a+18=7a
18=7a-1a
18=6a
6a=18
a=18/6
a=3
mariarad [96]3 years ago
3 0
Subtract the 1a from the 7a. 
1a + 18 = 7a
-1a          -1a

you're then left with 18=6a. divide the 6 with the 18 to cancel out.
18=6a
/6a /6a

18 divided by 6 is 3. So your answer is a=3
You might be interested in
The time for a visitor to read health instructions on a Web site is approximately normally distributed with a mean of 10 minutes
klio [65]

Answer:

a) The mean is 10 and the variance is 0.0625.

b) 0.6826 = 68.26% probability that the mean time of the visitors is within 15 seconds of 10 minutes.

c) 10.58 minutes.

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal Probability Distribution

Problems of normal distributions can be solved using the z-score formula.

In a set with mean \mu and standard deviation \sigma, the z-score of a measure X is given by:

Z = \frac{X - \mu}{\sigma}

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean \mu and standard deviation \sigma, the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean \mu and standard deviation s = \frac{\sigma}{\sqrt{n}}.

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

Normally distributed with a mean of 10 minutes and a standard deviation of 2 minutes.

This means that \mu = 10, \sigma = 2

Suppose 64 visitors independently view the site.

This means that n = 64,  = \frac{2}{\sqrt{64}} = 0.25

a. The expected value and the variance of the mean time of the visitors.

Using the Central Limit Theorem, mean of 10 and variance of (0.25)^2 = 0.0625.

b. The probability that the mean time of the visitors is within 15 seconds of 10 minutes.

15 seconds = 15/60 = 0.25 minutes, so between 9.75 and 10.25 seconds, which is the p-value of Z when X = 10.25 subtracted by the p-value of Z when X = 9.75.

X = 10.25

Z = \frac{X - \mu}{\sigma}

By the Central Limit Theorem

Z = \frac{X - \mu}{s}

Z = \frac{10.25 - 10}{0.25}

Z = 1

Z = 1 has a p-value of 0.8413.

X = 9.75

Z = \frac{X - \mu}{s}

Z = \frac{9.75 - 10}{0.25}

Z = -1

Z = -1 has a p-value of 0.1587.

0.8413 - 0.1587 = 0.6826.

0.6826 = 68.26% probability that the mean time of the visitors is within 15 seconds of 10 minutes.

c. The value exceeded by the mean time of the visitors with probability 0.01.

The 100 - 1 = 99th percentile, which is X when Z has a p-value of 0.99, so X when Z = 2.327.

Z = \frac{X - \mu}{s}

2.327 = \frac{X - 10}{0.25}

X - 10 = 2.327*0.25

X = 10.58

So 10.58 minutes.

6 0
3 years ago
Find the measures of the exterior angles of the polygon.
Len [333]

Step-by-step explanation:

180 - 34 = 146

one angle is a right angle, angle across it is 146, 360 - 90 - 146 = 124

divide that by two to get the measures of the remaining two angles (62 degrees)

180 - 62 = x

118 = x

4 0
3 years ago
Read 2 more answers
The area of a rectangular piece of cardboard is represented by
Liula [17]

This question is solved applying the formula of the area of the rectangle, and finding it's width. To do this, we solve a quadratic equation, and we get that the cardboard has a width of 1.5 feet.

Area of a rectangle:

The area of rectangle of length l and width w is given by:

A = wl

w(2w + 3) = 9

From this, we get that:

l = 2w + 3, A = 9

Solving a quadratic equation:

Given a second order polynomial expressed by the following equation:

ax^{2} + bx + c, a\neq0.

This polynomial has roots x_{1}, x_{2} such that ax^{2} + bx + c = a(x - x_{1})*(x - x_{2}), given by the following formulas:

x_{1} = \frac{-b + \sqrt{\Delta}}{2*a}

x_{2} = \frac{-b - \sqrt{\Delta}}{2*a}

\Delta = b^{2} - 4ac

In this question:

w(2w+3) = 9

2w^2 + 3w - 9 = 0

Thus a quadratic equation with a = 2, b = 3, c = -9

Then

\Delta = 3^2 - 4(2)(-9) = 81

w_{1} = \frac{-3 + \sqrt{81}}{2*2} = 1.5

w_{2} = \frac{-3 - \sqrt{81}}{2*2} = -3

Width is a positive measure, thus, the width of the cardboard is of 1.5 feet.

Another similar problem can be found at brainly.com/question/16995958

5 0
2 years ago
Choose the model for the problem 2/3 divided by 2.<br> 4/6<br> 1/6<br> 1/3<br> 2/3
olasank [31]

2/3 : 2 = 2/3 x 1/2 = 2/6 = 1/3

6 0
2 years ago
Read 2 more answers
PLS HELP ASAP FOR BRAINLIEST
rodikova [14]

Answer:

y=3

Step-by-step explanation:

it is because X=-2 had crossed the point y=3

hope this help you!!!! ;))))))

3 0
3 years ago
Other questions:
  • The function f(t) = 2.5t + 50 describes the total cost of ordering shirts, which includes the price per shirt and the one-time s
    7·1 answer
  • Are the expressions bh/2 and (1/2)bh equivalent expressions?
    8·1 answer
  • Explain how to use the combine place vales strategy to fine 223- 119
    5·1 answer
  • 1. A point on the ground is 50 feet from my house. The angle of elevation to the top of the house is 48 Find the height of the h
    15·1 answer
  • A 250-gal tank is initially filled with brine (salt-water mixture) containing 100 lb of salt. Brine containing 3 lb of salt per
    8·1 answer
  • Kyle is 12 years older than Susan. Last year, he was twice as old as Susan.
    6·1 answer
  • What would you do in order to write 1/5x +<br> 1/3y = 9 in standard form?
    6·1 answer
  • A $400 table is on sale for 33% off. There is a 6.8% sales tax. How would you find the final price of the table?
    7·2 answers
  • Which physical feature is shown?
    6·1 answer
  • Pls explain why its a yes pleasee and thx u​
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!