The ordered pair are a set of (x,y) points. To check if the point is a solution for a given equation, replace one of the points into the equation.
In this case, since x=0, it is the simplest to check.
0 + 2y = 3
y = 3/2
Since this matches the ordered pair the answer is TRUE. If we had arrived at any answer other than 3/2 than the ordered pair would not have been a solution set. We would have arrived at the same answer had 3/2 been placed in the equation for y.