Cheryl had twice as much money as Daphne at first. Each day, Daphne spent $8 while Cheryl spent $2 lesser. When Daphne had spent all her money, Cheryl still
had $70. How many days did Daphne take to spend all her money?

Integers may be positive or negative. They are whole numbers. 
Rational expression is a fraction wherein a numerator and/or a denominator are polynomials.

Division of integers is like dividing whole numbers. You only have to take not of the positive or negative sign of each integer to determine the sign of the quotient.

Division of rational expression:
1) flip and multiply
2) factor the numerator and denominator
3) cancel duplicate factors and simplify.