Expand and simplify: (x+3)(x+5)(x + 3)(x + 5)(x+3)(x+5).
x2+8x+15x^2 + 8x + 15x2+8x+15
x2+15x+8x^2 + 15x + 8x2+15x+8
x2+8x+8x^2 + 8x + 8x2+8x+8
x2+15x^2 + 15x2+15