Please help me grades all most here

If f(x)=2x-6 and g(x)=3x+9, find (f-g)(x)

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

What effect would doubling all the dimensions of a triangular pyramid have on the volume of the pyramid? explain your reasoning.