Can someone help solve this problem?

Question

-2(z-1)≤20 and 8-z<11 
I solved this and got the correct answer which is [-9,∞) for the first one and (-3,∞) for the second one. Now I am being asked to describe the overall solution set using interval notation and to enter my answer in decimal form. This is the part that confuses me. Can someone please explain?

Answer 1

The inequality is -2(z - 1) ≤ 20 and its solution is [-9, ∞).

The inequality is 8 - z < 11 and its solution is (-3, ∞).

The solution of the compound inequality is -2(z - 1) ≤ 20 and 8 - z < 11 is (-3, ∞) and its graph is