Can someone me with these 2 questions?

The factorization of 8x3 -125 is (2x-5)(jx2 +kx+25)

Assume that the weights of quarters are normally distributed with a mean of 5.67 g and a standard deviation 0.070 g. a vending machine will only accept coins weighing between 5.48 g and 5.82 g. what percentage of legal quarters will be rejected? round your answer to two decimal places.

What does independent variable and dependent variable mean in math?