Factorising QuadraticsWendy’s Way

Factorise

6x2 + 25x 9

First Last

6 9

=54

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 +10First Last

12 10

= 120

Factors of 120

1 120 2 60

3 40 4 30

5 24 6 20

8 1510 12

Find factors which give 26

12x2 + 6x + 20x + 10And split expression

Factorise6x(2x + 1) + 10(2x + 1)

(6x + 10)(2x + 1)

Now try these

6x2 + 5x - 6

6 6 = 361 362 183 124 96 69 - 4 = 5

6x2 + 9x 4x 63x(2x + 3) 2(2x + 3)

(3x 2)(2x + 3)

6x2 - 17x - 14

6 14 = 841 842 243 284 216 147 12

4 21 = 176x2 +4x 21x 14

2x(3x + 2) 7(3x + 2)(2x 7)(3x + 2)