What exactly do you mean by "solve a system of linear inequalities?" Find a point that lies in their intersection? That's exactly what the first phase of the revised simplex method does. If it's just in two dimensions (two variables) though, it would easier to just do it graphically. This software works wonders: http://www.padowan.dk/graph/
Technological development has always been on an exponential curve. Here's a challenge: Open your default graphing program (or download Graph, which is free). Press Ctrl+A to open the axis settings. Name the x-axis "millenniums" and the y-axis "technological progress". How, make the maximum value of x 50. This is the equivalent of 50,000 years. Press "OK" to get back to the program. Now, type in the function "f(x)=1.03^x -1". This is an exponential function. You should get a graph that is very slowly rising. Now, go back to the axis options and make the maximum x-value 100. You will see a dramatic increase in progress. This is what exponential functions do. At first, there will always be very little change, which will suddenly burst in a huge amount of increase.
TL;DR: A simple mathematical formula can answer your father's question.