2x^2-12x+6=0 how to solve

Simplify (a/b - b/a) times (a - a^2/a+b) a - a^2/a=b is a mixed number

Can someone me and do the problem plz so i can understand it more better

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