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)

shaalaa.com

Factorisation by Grouping

Is there an error in this question or solution?

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

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

Factorise by the grouping method : ab - 2b + a² - 2a

Factorise by the grouping method :
`a^2 + 1/a^2 - 2 - 3a + 3/a`

Factorise : 6a² - 3a²b - bc² + 2c²

Factorise : (a² − b²) c + (b² − c²)a

Factorise : 2ab² - aby + 2cby - cy²

factorise: 2a² - 17ab + 26b²

factorise: 4c² + 3c - 10

factorise: b(c - d)² + a(d - c) + 3(c - d)

Factorise the following by grouping the terms:
9 + 3xy + x²y + 3x

Factorise the following by grouping the terms:
2a + b + 3c - d + (2a + b)³ + (2a + b)²(3c - d)