Hey there!
To find the value of f(-2), first locate a point on your graph with -2 as its x value. To do this, locate -2 on the x axis and move towards the function. When you do, you should find the point (-2, 4).
Therefore, your answer would be the y-value of the point, 4.
To find the value of f(5), you would do the same as above. When you locate your point, you should find (5,3).
Therefore, your answer would be the y-value of the point, 3.
Hope this helps! :)