Question 75054
Factor:
{{{25x^2-81y^2}}} Do you recognise this as the difference of two squares?
{{{(5x)^2-(9y)^2}}}
The difference of two squares is factored thus:
{{{A^2-B^2 = (A-B)(A+B)}}} Applying this to your problem:
{{{(5x)^2-(9y)^2 = (5x-9y)(5x+9y)}}}