What have you done so far?
For a) you should just plot some points. For example choose x to be -3,-2,-1,0,1,2,3 and then if you need to you can plot more points in between to get a nice curve. Then using the graph, you can find approximately where the min/max occur.
For b) You can use the plot you just made. Intervals of increase are intervals where if x is increasing so is f(x). It's the opposite for intervals of decrease. The slope of the tangent, you can either use the derivative to calculate it, or you can just use the approximation rise/run from the points you plotted.
For c) i think you need to actually calculate it.
For d) you do need the data from c)