When my teacher says find (a) but i found it, what does she mean?

Which is the completely factored from of xy^3-x^3y

Which of the statements about the graph of the function y = 2x are true? check all of the boxes that apply. the domain is all real numbers x because the exponent of 2 can be any real number when the x-values increases by 1 unit, the y-value multiplies by 2. the y-intercept is (0, 1). the graph never goes below the x-axis because powers of 2 are never negative. the range is all real numbers.

What are the domain and range of f(x)= -log5(x+2)