Question 78158
Factor the binomial:
{{{25x^2-81y^2}}} This is the difference of two squares:{{{(5x)^2-(9y)^2}}}.
The difference of two squares can be factored thus:
{{{A^2-B^2 = (A+B)(A-B)}}} Applying this to the given binomial, you get:
{{{25x^2-81y^2 = (5x+9y)(5x-9y)}}} which is exactly what your last line shows.