What is a direct application to graphing a linear equation?

given a set of data points (typically used in statistical methods), you can find a linear function that best approximates your data using a method known as least squares.

there arent, the government needs us to be taught crap that we are going to forget in 5 years time, according to probability one in each and every 10000 scholars will do some lame pastime with physics and prefer it??