Problem 13 - Elementary Algebra

Question

Find the value of each of the following expressions. $$ (-2)(-8) $$

Step-by-Step Solution

Answer

Answer: 16

Step 1: Multiply the numbers together

To find the value of the expression, we need to multiply the numbers -2 and -8 together. Remember that the product of two negative numbers is a positive number. Therefore, we have: $$ (-2)(-8) = 2 \cdot 8 $$

Step 2: Calculate the product

Now we simply need to calculate the product of 2 and 8: $$ 2 \cdot 8 = 16 $$ So the value of the given expression is 16.

Key Concepts

Elementary Algebra

Algebra is like a universal puzzle where we use numbers, symbols, and letters to represent relationships and solve problems. In elementary algebra, basic arithmetic operations - addition, subtraction, multiplication, and division - are used to simplify expressions and solve equations. For instance, when we encounter a problem like multiplying two negative numbers, algebra teaches us not just how to find the answer but also why the rules work as they do.

Understanding the fundamental principles of algebra, such as the concept of variables and constants, can help unlock the meaning behind the numbers. In your homework where you multiplied \( -2 \) by \( -8 \) to get 16, you were applying these foundational algebraic principles. By digging deeper into these concepts, students can learn to solve complex problems with ease, making algebra a powerful tool in both education and practical life.

Product of Negative Numbers

The product of negative numbers can be bewildering at first glance. To understand why the multiplication of negatives results in a positive, it helps to think about it in terms of loss or absence. For example, if losing money is represented by a negative number, then losing a debt (which is itself a negative because it's an absence of money) is like gaining money - hence a positive.

So, when you multiply \( -2 \) and \( -8 \) together, you are essentially combining two 'losses', which result in a 'gain'. In technical terms, the rules we use state that a negative multiplied by a negative gives a positive. This rule is a fundamental building block in arithmetic and is vital for students to remember when tackling algebraic equations.

Basic Arithmetic Operations

Arithmetic is the branch of mathematics that deals with numbers and the basic operations: addition, subtraction, multiplication, and division. Each of these operations has its own set of rules, especially when dealing with positive and negative numbers.

In our example with multiplying \( -2 \) by \( -8 \) we focus on multiplication. This specific operation has a very straightforward rule when it comes to negatives: multiplying a negative by a negative produces a positive, while multiplying a negative by a positive yields a negative. This simplicity and orderliness make arithmetic feel almost like a dance with numbers. For students to feel in step with the rhythm of mathematics, it is essential that they practice these operations until they become second nature.