Can negative exponent converted to positive exponent when multiplying or dividing monomials or binomials by trinomials?

Do you always use the property of distribution when multiplying monomials and polynomials?

Multiply the monomial by the binomial and find the value for x = 3, y = 1.25 → xy (x² + y²)? Round up the answer

Multiply the monomial by the binomial and find the value of each for x = 3, y = 1.25 and z = 0.002 → z² (3x - 2y)?

Multiply the monomial by the binomial and find the value of each for x = 3, y = 1.25 → xy (x² + y²)?

Multiply the monomial by the binomial and find the value of each for x = 3, y = 1.25 and z = 0.002 → z² (3x + 2y)?