Factorise: A2 - 23a + 42

factorise: a² - 23a + 42

Sum

a² - 23a + 42 ...[42 = 21 × 2 and 21 + 2 = 23]

= a² - 21a - 2a + 42

= a(a - 21) - 2(a - 21)

= (a - 21)(a - 2)

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Factorisation by Grouping

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Chapter 13: Factorisation - Exercise 13 (F) [Page 163]

Chapter 13 Factorisation
Exercise 13 (F) | Q 4.1 | Page 163

Factorise by the grouping method : a³ + a - 3a² - 3

Factorise by the grouping method : a⁴ - 2a³ - 4a + 8

Factorize using the grouping method:

x² + y² + x + y + 2xy

Factorise using the grouping method :
x (6x - 5y) - 4 (6x - 5y)²

Factorise : ax + 2bx + 3cx - 3a - 6b - 9c

factorise: a² − 3a − 40

factorise: 4 + y - 14y²

factorise: 5 - 4x(1 + 3x)

factorise: ax² + b²y - ab² - x²y

Factorise the following by grouping the terms:
x² - (p + q)x + pq