Problem 57 - BIG IDEAS MATH Algebra 2: Common Core Student Edition 2015

Question

Write the prime factorization of the number. If the number is prime, then write prime. 79

Step-by-Step Solution

Answer

79 is a prime number.

Step 1: Identify if the number is a Prime

For the number 79, check for any divisors other than 1 and itself. Remember, a number is prime if it does not have any other divisors. For the number 79, no such divisors exist, meaning 79 is a prime number.

Step 2: Record the result

Since 79 is a prime number, there is no need for prime factorization. The number is prime in its current form.

Key Concepts

Prime Numbers

When we talk about prime numbers, we're referring to those special numbers greater than 1 that have exactly two distinct natural number divisors: 1 and themselves. They are the building blocks of all natural numbers because any non-prime number can be factored into a product of primes. This distinctive quality is significant because it means primes cannot be divided evenly by any other numbers.

Finding out whether a number is prime involves testing its divisibility by all natural numbers up to its square root. For example, in the exercise with the number 79, it was determined to be prime because it couldn't be evenly divided by any number other than 1 and 79. Teaching tip: A helpful exercise improvement advice is to have students create a list of primes or to use a divisibility rule to quickly eliminate potential divisors.

Divisibility

The concept of divisibility is essential for understanding prime factorization. A number is said to be divisible by another if, upon division, the result is an integer with no remainder. For example, 15 is divisible by 3 because 15 divided by 3 equals 5, a whole number, without any remainders.

To enhance understanding, one can explore various divisibility rules, such as those for 2, 3, 5, 9, and 10. For instance, any number ending in an even digit is divisible by 2, while a number is divisible by 3 if the sum of its digits is divisible by 3. Students can apply these rules to check for factors when doing prime factorization. An exercise improvement could be to get students to practice these rules by applying them to several numbers to determine their divisibility.

Algebra 2

Algebra 2 often involves the application of prime numbers and factorization within more complex mathematical problems. It builds on the principles learned in earlier algebra courses, such as expressions, equations, and factoring, and introduces more advanced topics. These may include polynomial division, synthetic division, and rational expressions.

When talking about prime factorization in Algebra 2, it can serve as a tool to simplify algebraic fraction expressions. For instance, reducing fractions to their simplest form requires the prime factorization of the numerator and denominator. Students might also encounter prime factorization when working with least common multiples (LCMs) and greatest common divisors (GCDs), helping to build their problem-solving skills. An area for exercise improvement might include demonstrating how prime factorization is used in the simplification of algebraic expressions.