Question

Factorise the following expression-
a^2 - ab - 20b^2
PLEASE ANSWER IT FAST!!!
ITS URGENT!!!
PLEASEEE

Answer 1

Here is your answer

$a {}^{2} - ab - 20b {}^{2} \\ = a {}^{2} - 5ab + 4ab - 20b {}^{2} \\ = a(a - 5b) + 4b(a - 5b) \\ =( a - 5b)(a + 4b)$
Hope it helps you