Can you guys me with these questions

2.5 milligrams is equivalent to how many grams

In a small section of a stadium there are 40 spectators watching a game between the cook islands and fiji. they all support at least one of the two teams. 25 spectators support the cook islands and 16 of these support both teams. how many support only fiji?

Use the zero product property to find the solutions to the equation (x+2)(x+3)=12