0.156 divided by 0.13

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

1) prove that 731^3−631^3 is divisible by 100 2) prove that 99^3−74^3 is divisible by 25

An object in geometry with no width, length or height is a(n):