As a starter, the y value is equal to f(x); the x value is equal to the x in f(x).
So basically, in this case, replace x with the number in the brackets.
Coordinates have x, y values (x, y). Here, we know x is -2, so we need to find y.
on the graph, find x = -2 and find where the line of the drawn graph intersects it. Looks like the line intersect x = -2 when y = 3. So f(-2) = 3.
Same applies for b: x = 0, find where the line hits x = 0, and that's your y value, which is 1.
Tried my best to simplify it. Hope it helps lol.