Factorisation of Quadratic expression Flashcards
The cross method is also known as the _______ ?
The trail and error method as we may require to try different combinations to arrive at the correct answer
ax2 + bx + c
what does a, b and c represent
a is the coefficient of x2
b is the coefficient of x
c is the constant
If a = 1
x2 + bx + c
how to find the factors of the expression
The factor is such that
c is divided into its factors such that when the factors are added up, they will equal to b
Factorise x2 + 5x + 6
Rewrite the expression such that the middle and the third interchange
Factorise x2 + 5x + 6
List out the factors of 6
the factors of 6
1 * 6
2 * 3
- 1 * (-6)
- 2 * (-3)
Factorise x2 + 5x + 6
Select the pair of factors that add up to 5
1 + 6 = 7 (no)
2 + 3 = 5 (yes)
- 1 + (-6) = -7 (no)
- 2 + (-3) = -5 (no)
Factorise x2 + 5x + 6
What is the final answer?
arranged horizontally
(x + 2)(x + 3)
Factorise x2 - 5x + 6
Rewrite the expression such that the middle and the third interchange
Factorise x2 - 5x + 6
List out the factors of 6
the factors of 6
1 * 6
2 * 3
- 1 * (-6)
- 2 * (-3)
Factorise x2 - 5x + 6
Select the pair of factors that add up to -5
the factors add up to -5
1 + 6 = 7 (no)
2 + 3 = 5 (no)
- 1 + (-6) = -7 (no)
- 2 + (-3) = -5 (yes)
Factorise x2 - 5x + 6
What is the final answer?
arranged horizontally
(x - 2)(x - 3)
Factorise x2 - x - 6
Rewrite the expression such that the middle and the third interchange
Factorise x2 - x - 6
List out the factors of -6
- 1 * 6
- 2 * 3
1 * (-6)
2 * (-3)
Factorise x2 - x - 6
Select the pair of factors that add up to -1
the factors add up to -1
- 1 + 6 = -5 (no)
- 2 + 3 = 1 (no)
1 + (-6) = 5 (no)
2 + (-3) = -1 (yes)
Factorise x2 - x - 6
What is the final answer
Arranged horizontally
(x - 3)(x + 2)
