hi this is my question, i need to factorise this:
x^2 - 81?
im having a few problems with factorising at the moment so could someone let me know how to work this out!
would i be correct if i did this (x^2 - 81)??
Thanks
No, that's still the original problem.
This question is classic difference of two squares: . To make it more apparent you can write it as
http://en.wikipedia.org/wiki/Difference_of_two_squares