9 + -4 --7 X -3<br> Evaluate the expression?

Question 9. True or false? Provide a simple counter-example if it is false. (9.a) The sum of two rational numbers x, y EQ is alw

eimsori [14]

Answer:

a. True. Rational numbers are closed under the sum operation, therefore, the sum of two rational numbers is always a rational number.

b. True. irrational numbers are closed under the sum operation, therefore, the sum of two irrationals numbers is always a irrational number.

c. True. The square of a real number is always a number greater than zero, and the sum of two numbers greater than zero is greater than zero.

d. True. The real numbers are closed under the product operation, then if a and b are reals numbers, the product ab is also a real number.

Step-by-step explanation:

8 0

3 years ago

The SAT Reasoning Test (formerly called the Scholastic Aptitude Test) is perhaps the most widely used standardized test for coll

mihalych1998 [28]

Given Information:

Mean SAT score = μ = 1500

Standard deviation of SAT score = σ = 3 00

Required Information:

Minimum score in the top 10% of this test that qualifies for the scholarship = ?

Answer:

$\bar{x} = 1884\\$

Step-by-step explanation:

What is Normal Distribution?

We are given a Normal Distribution, which is a continuous probability distribution and is symmetrical around the mean. The shape of this distribution is like a bell curve and most of the data is clustered around the mean. The area under this bell shaped curve represents the probability.

We want to find out the minimum score that qualifies for the scholarship by scoring in the top 10% of this test.

$P(X > \bar{x} )= P(Z > \bar{x}) = 0.10\\P(X < \bar{x} )= P(Z < \bar{x}) = 1 - 0.10\\P(X < \bar{x} )= P(Z < \bar{x}) = 0.90\\$

The z-score corresponding to the probability of 0.90 is 1.28 (from the z-table)

$\bar{x} = \mu + z(\sigma) \\\bar{x} = 1500 + 1.28(300)\\\bar{x} = 1500 + 384\\\bar{x} = 1884\\$

Therefore, you need to score 1884 in order to qualify for the scholarship.

How to use z-table?

Step 1:

In the z-table, find the probability value of 0.90 and note down the value of the that row which is 1.2

Step 2:

Then look up at the top of z-table and note down the value of the that column which is 0.08

Step 3:

Finally, note down the intersection of step 1 and step 2 which is 1.28

4 0

2 years ago

Determine the slope of the line segment<br> A.) 2<br> B.) 5<br> C.) 1/2<br> D.) 5/3

ohaa [14]

up 5

over to the right 3

rise/run

5/3

Choice D

6 0

3 years ago

Please solve with explanation

OverLord2011 [107]

Real life scenarios of acute angles are:

Sighting a ball from the top of a building at an angle of 55 degrees.
The angle between two adjacent vanes of a fan that has 6 vanes

<h3>What are acute angles?</h3>

As a general rule, an acute angle, x is represented as: x < 90

This means that acute angles are less than 90 degrees.

<h3>The real life scenarios</h3>

The real life scenarios that involve acute angles are scenarios that whose measure of angle is less than 90 degrees.

Sample of the real life scenarios that satisfy the above definition are:

Sighting a ball from the top of a building at an angle of 55 degrees.
The angle between two adjacent vanes of a fan that has 6 vanes

9 + -4 --7 X -3 Evaluate the expression?