Step #1 for both: figure out which interval your x-value fits into. For f(-2), x=-2 and -2 fits with x ≤ -2, the top interval. For f(3), x=3 and 3 fits into -2 < x ≤ 3, the middle interval.
Step #2 for both, plug in your x-value to the piece of the function that fits with that interval. For f(-2), we know x≤-2, so we use 2x+8 to evaluate x=-2. For f(3), we know -2 f(-2) = 2(-2)+8 = -4+8 = 4
