Question

Factorise fully
16a²-121b²​

Answer 1

Explanation:

Rule: (a^2-b^2)=(a-b)(a+b) (‘difference of squares’)

16a^2-121b^2

(4a-11b)(4a+11b)

Answer 2

(4a - 11b)(4a + 11b)

Explanation:

16a² - 121b² ← is a difference of squares and factors in general as

a² - b² = (a - b)(a + b) , then

16a² - 121b²

= (4a)² - (11b)²

= (4a - 11b)(4a + 11b)