Find a factor of $x^{2} - 121y^{2}$.

Find a factor of $x^{2} - 121y^{2}$.
  1. $x - 11y$
  2. $x - 121y$
  3. $x^{2} + 11y$
  4. $x + 121y$

Solution

$x^{2} - 121y^{2} = x^{2} - (11y)^{2} = (x-11y)(x+11y)$.

Asked in: IMO

Practice more ALGEBRAIC EXPRESSIONS AND IDENTITIES questions on Aicharya