What is an a priori proposition? an a posteriori proposition?

Ajar of gumballs contains 4 reds, 2 greens, and 6 blues. what is the probability of getting two blues in a row without replacement?

Express in the simplest form: (x^2+9x+14/x^2-49) / (3x+6/x^2+x-56)

What is the quotient of m^6/5 ÷ 5/m^2? assume m does not equal pl