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Learn it your way
A short class with Sarah and her students. The other ways are under More.
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Today, we're going to explore what factors are! Who can tell me what they think factors are?
I think factors are numbers that can multiply together to get another number.
Exactly! For example, 30 can be broken down as 2 times 15. And what about its prime factors?
A prime factor is a factor that is a prime number, right? Like 2, 3, or 5 for 30?
Great! So the prime factors of 30 are 2, 3, and 5. Remember, every number has at least two factors: itself and 1. We'll use this knowledge in factorisation.
Can anyone tell me why we write 30 as a product of its prime factors?
It's because it makes it easier to see how the number is built up!
Exactly! So remember: factors and prime factors help us in breaking down and understanding numbers.
To remember this, think of the acronym 'FARM' — Factors Are Really Magnificent!
Moving on, let's talk about algebraic expressions. Who can give me an example of an algebraic expression?
Like 5xy + 3x?
Exactly! And can you identify the factors in the term 5xy?
The factors are 5, x, and y!
Correct! We call these 'irreducible' factors. They can’t be simplified further. What's another example?
3x(x + 2)!
Perfect! Now, to find the factors of more complex expressions, what strategy do we use?
We look for common factors first!
Exactly! Remember the phrase 'Check Commonly!' to remind yourself.
Let's dive into methods of factorisation. Who remembers the first technique we discussed?
Finding the common factors!
That's right! Let's factor 2x + 4 together.
2x = 2 × x and 4 = 2 × 2, so it's like 2(x + 2)!
Correct! Now, what if we don't have a common factor across all terms?
We can regroup the terms!
Exactly! Regrouping allows us to create groups that share common factors. Now let's try that with the expression 2xy + 2y + 3x + 3.
We can group 2xy + 2y together and 3x + 3 together!
Absolutely! And when we factor out, we end up with (x + 1)(2y + 3). Knocking down expressions, one factor at a time — remember 'KNOCK!'
Now, let's explore factorisation using identities. For instance, can someone tell me a useful identity?
Yeah! (a + b)² = a² + 2ab + b²!
Exactly! And we can recognize this form in expressions? For example, x² + 8x + 16.
It fits the identity for a perfect square!
Perfect! When we see such patterns, we can factor using the identities we've learned. Can anyone tell me how this can simplify expressions?
It makes it much easier to factor without expanding them manually!
Wonderful! Remember the identity is like a magic key, allowing you to open doors to easier factorisation. Just think 'MAGIC KEY!'
Let's switch gears to division of algebraic expressions. Can someone summarize how division relates to what we've learned about multiplication?
Division is the opposite of multiplication!
Exactly! For example, if I take 6x³ and want to divide it by 2x, what would that look like?
It simplifies to 3x²!
Right you are! We can simplify the expression based on common factors. What's important to note here?
We can use factorisation to make division easier!
Yes! So remember this: 'Facts to Simplify!' when dividing.
Numbers or expressions multiplied to yield another number or expression.
The simplest form of factors that cannot be simplified further.
The method of expressing expressions or numbers as products of their factors.
A shared factor amongst given terms used in factorization.
A strategic rearrangement of terms to facilitate the identification of common factors.
Fundamental equations that help in simplifying and solving expressions.
Factors come in pairs, big and small, When multiplied together, they answer the call!
Once there was a number named 30 who had many friends—1, 2, 3, all the way to 30! They would all gather and multiply to create new friends.
To remember factor pairs can use the phrase 'Pull and Pair!'—pull out common factors and pair the others.
F.A.C.T.S. — Factors Are Crucial To Simplifying.
Term
What are factors?
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Define irreducible factors.
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What is factorisation?
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Explain regrouping.
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Numbers or expressions that are multiplied together to get another number or expression.
Factors that cannot be expressed as a product of further simpler factors.
Factors that are prime numbers, meaning they only have two distinct positive divisors: 1 and themselves.
The process of expressing a number or algebraic expression as a product of its factors.
A number or expression that divides two or more numbers or terms evenly.
A method of arranging terms in an expression to find common factors.
Equations that are true for all values of the variable(s) involved.
An algebraic expression in the form a² - b², factorable into (a + b)(a - b).
This section covers the concept of factorisation, emphasizing how numbers and algebraic expressions can be expressed as products of factors.
The section explores the definitions of factors of natural numbers and algebraic expressions, different methods of factorisation including common factors and regrouping, and introduces several identities useful for factorisation. It also provides methods for dividing algebraic expressions.
In this section, we learn about factorisation, specifically how both natural numbers and algebraic expressions can be expressed as products of their factors.
We recall the definition of factors, with examples using numbers like 30 (whose factors include 1, 2, 3, 5, 6, 10, 15, and 30). We highlight prime factors, explaining that a number expressed as a product of prime factors is in its prime factor form (
In algebra, terms are products of factors; for instance, in the expression 5xy + 3x, the term 5xy consists of the factors 5, x, and y. We redefine 'prime' factors as 'irreducible' factors in terms of algebra.
Factorisation is explained as writing an algebraic expression or number as the product of factors, distinguishing between expressions already in factor form and those requiring methods to factor them systematically.
This section also introduces various identities (like the square of a binomial and the difference of squares) which assist in factorising specific expressions.
Finally, we cover how to divide algebraic expressions, including the division of monomials and polynomials by monomials and other polynomials, emphasizing that we can factor out common terms and simplify expressions accordingly.