Question

(a) Factorise x^2-9.
(b) Use your answer to part (a) to find two factors of 9991, other than 1 and 9991.

Answer 1

I know (A) is (x-3)(x+3). But I don't know how to do part (b).

Answer 2

9991=(x+3)(x-3)=x^2-9
10000=x^2
x=100
9991=(100+3)(100-3)
9991=103*97

Answer 3

Oh ... lol
sorry

Answer 4

Thank you.

Answer 5

Sure thing :)