Considering this situation you've given. The fastest way for me
would be to plot it out on graph paper and find all the values.
Serious. I know its stupid and old fashion and yada yada yada. But
if none of the software works for me, the fastest, most practical
way for me to do is on paper.
At uni level, hand written work is still very much appreciated. No
such thing called:"Computer can give nicer graphics lah.", all that
excuse, phooey. 
Btw, gradient is change of y over change of x.
