If the denominator is less than 1 then invert it and multiply the polynomial numerator. If the denominator is x and 0<x<1 (that is, positive but less than 1), multiply the polynomial by x, whether x is an actual number or a variable.
Example: 2x^2-3x+5 divided by 1/5 or 0.2. The polynomial becomes 10x^2-15x+25.
If x<0 but still a fraction, the same thing applies but the polynomial is negated as well. So in the above example if the denominator is -0.2, the polynomial becomes -10x^2+15x-25.