I need help with this

Identify a1 and r for the geometric sequence an= -256(-1/4) n-1

What two criteria are needed for triangles to be similar

What is the multiple zero and multiplicity of f(x) = (x ? 3)(x ? 3)(x + 5)? multiple zero is 3; multiplicity is 2 multiple zero is 5; multiplicity is 1 multiple zero is ? 5; multiplicity is 1 multiple zero is ? 3; multiplicity is 2