What is the answer to w is no less than 0

How do you use the elimination method for this question? explain, because i really want to understand!

The swimming pool is open when the high temperature is higher than 20∘c. lainey tried to swim on monday and thursday (which was 33 days later). the pool was open on monday, but it was closed on thursday. the high temperature was 30 ∘c on monday, but decreased at a constant rate in the next 33 days. write an inequality to determine the rate of temperature decrease in degrees celsius per day, d, from monday to thursday.

Graph y ≥ -x^2 - 1. click on the graph until the correct graph appears.