Question

Factorisea 2–23a+42​

Answer 1

a2 – 23a + 42

[42 = 21 × 2 and 21 + 2= 23]

= a2 – 21a – 2a + 42 = a (a – 21) – 2 (a – 21)

= (a – 21) (a – 2)

Answer 2

Answer:

a²-2a-21a+42

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

(a-2) (a-21)