Question

Find the value using algebraic formula.

9998² – 9999 × 9997

Answer 1

Given: 9998² – 9999 × 9997

Let 9998 = x then 9999 = (x + 1) and 9997 = (x – 1)

∴ 9998² – 9999 × 9997 = x² – (x + 1) (x – 1)

We know that,

(a + b) (a – b) = a² – b²

Hence,

⇒ x² – (x² – 1)

⇒ 1