When graphing inequalities why do you use closed or open dot?

While scuba diving, rajeev dove to a depth of 12.6 feet below the surface of the water and then descended another 8.7 feet. what expression can be used to find rajeev's new position? 12.6 – 8.7 –12.6 – 8.7 –12.6 – (–8.7) 12.6 – (–8.7)

What is the equation of a line passing through (-6,5) and having a slope of 1/3

What are the domain and range of f(x)= -log5(x+2)