What is the answer? i dont get it

In simplified exponential notation, the expression a^2•a^-3•a 1/a 0

Which of the following is true for the relation f(x)=2x^2+1

Aportion of a hiking trail slopes downward at about an 84° angle. to the nearest tenth of a flot, what is the value of x, the distance the hiker traveled along the path, if he has traveled a horizontal distance of 120 feet? a. 143.3 b. 12.5 c. 120.7 d. 130.2