Zusammenfassung der Ressource
Factorisation
- The opposite of expanding
- Process
- Step 1- Check for common factors
- Step 2- Count the number of terms
- If there are 2 terms check for DOPS OR grouping 2 & 2
- If there are 3 terms check for perfect square OR trinomial
- Always check your answer for a common factor OR like terms OR DOPS
- Common Factors
- If there are already brackets in the question, expand the brackets and then factorise
- 6(x-1)+2 = 6x-6+2 = 6x-4 = 2(3x-2)
- Placed outside the bracket
- 2x-4y= 2(x-2y)
- DOPS
- Difference of Perfect Squares OR Difference of Two Squares (DOTS)
- Looks like a^2 * b^2
- Always check for a common factor first
- 2x^2 -50 = 2(x^2 -25) = 2(x^2 -5^2) = 2(x-5)(x+5)
- Example
- x^2-4 = x^2 - 2^2 = (x-2)(x+2)
- Grouping 2 & 2
- When you have 4 terms with no obvious common factor, sometimes it is easier to group the ones with common facotors
- Once grouped, take out the common factor from each of the brackets
- Try to have the same thing inside both brackets
- Place the thing inside the brackets in it's bracket out the front. Place what is left in the second bracket
- Example
- 3y^2 - 2xy - 6y +4x = y(3y-2x) -2 (3y-2x) = (3y-2x)(y-2)