How to add or subtract radians? for example: pi/3 - pi/6 ?

the solution is h=10 because you add 9 to each side of the equation.

answer: domain and range mean all possible values of x and y that could be substituted to the inequality. a solution means all possible values that make the inequality statement true. so while the range is still all real numbers, the solution is the shaded area, for which y will always be greater than the line of the function.