First simplify the equation by distibuting
3(x+5)(x+5) + 27(x-5)-66 becomes
3x^2 + 30x + 75 + 27x - 135 - 66
simplify
3x^2 + 57x - 126
factor out a gcf
3(x^2 + 19x - 42)
then factor once more to recieve
3(x + 2)(x -21)
Did you write the problem incorrectly?