Question

x2- 12x - 45 factorise
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Answer 1

Step-by-step explanation:

1

Use the sum-product pattern

2

−

1

2

−

4

5

x^{2}{\color{#c92786}{-12x}}-45

x2−12x−45

2

+

3

−

1

5

−

4

5

x^{2}+{\color{#c92786}{3x}}{\color{#c92786}{-15x}}-45

x2+3x−15x−45

2

Common factor from the two pairs

2

+

3

−

1

5

−

4

5

x^{2}+3x-15x-45

x2+3x−15x−45

(+3)−15(+3)

x(x+3)-15(x+3)

x(x+3)−15(x+3)

3

Rewrite in factored form

(+3)−15(+3)

(−15)(+3)