Since, from looking at the graph, you know that (10,10) is a point in the shaded area, you can substitute it into the equations.
10>or equal to -4/5(10)+8 -- 10> or equal to 0, which is true, then 10> or equal to 1/2(10)+3 -- 10 > or equal to 8, which is true. You know it's greater than or equal to because the lines are solid, making the answer letter D.