(3-4x)^2 / (x-3)^2 - (x+3)^2
= (9 - 24x + 16x^2) / (x^2 - 6x + 9) - (x^2 + 6x + 9)= (16x^2 - 24x + 9) / (x^2 - 6x + 9) - (x^2 + 6x + 9)
= (16x^2 - 24x + 9 - x^2 - 6x - 9) / (x^2 - 6x + 9)= (15x^2 - 30x) / (x^2 - 6x + 9)= 15x(x - 2) / (x - 3)^2
Therefore, the simplified expression is 15x(x - 2) / (x - 3)^2.
(3-4x)^2 / (x-3)^2 - (x+3)^2
= (9 - 24x + 16x^2) / (x^2 - 6x + 9) - (x^2 + 6x + 9)
= (16x^2 - 24x + 9) / (x^2 - 6x + 9) - (x^2 + 6x + 9)
= (16x^2 - 24x + 9 - x^2 - 6x - 9) / (x^2 - 6x + 9)
= (15x^2 - 30x) / (x^2 - 6x + 9)
= 15x(x - 2) / (x - 3)^2
Therefore, the simplified expression is 15x(x - 2) / (x - 3)^2.