Transcript Wendy`s way version 2

Factorising Quadratics
Wendy’s Way
Factorise
6x2 + 25x  9

First
6

=54
Last
9
6x2 +25x - 9
Write Factors of 54
1
54
2
27
3
18
6
9
Find combination to give
+25
27  2
Split expression into 2 parts 6x2 +27x  2x  9
Factorise each part 3x(2x+9)  1(2x+9)
This gives the factors (3x  1)(2x + 9)
Now try to Factorise
12x2 + 26x + 10
12x2 + 26x +10
First  Last
12  10
= 120
Factors of 120
1  120
2  60
3  40
4  30
5  24
6  20
8  15
10  12
Find factors which give 26
And split expression
12x2 + 6x + 20x + 10
Factorise
6x(2x + 1) + 10(2x + 1)
(6x + 10)(2x + 1)
Now try these
6x2 + 5x - 6
6  6 = 36
1  36
2  18
3  12
49
66
9-4=5
6x2 + 9x  4x  6
3x(2x + 3)  2(2x + 3)
(3x  2)(2x + 3)
6x2 - 17x - 14
6  14 = 84
1  84
2  24
3  28
4  21
6  14
7  12
4  21 =  17
6x2 +4x  21x  14
2x(3x + 2)  7(3x + 2)
(2x  7)(3x + 2)