Before computers became ubiquitous and cheap if one wanted to know the the first 5 decimals of 5/sqrt(2) you had to look up the result in a table of values. Bu

Before computers became ubiquitous and cheap if one wanted to know the the first 5 decimals of 5/sqrt(2) you had to look up the result in a table of values. But to save space and printing cost that table of values did not contain 1/sqrt(2). It did contain sqrt(2). My comment about quadratic and linear equations was to point out that pretty much most of basic algebra is realizing that these are the only two types of equations that can be solved by hand (ignore 3rd and 4th degree formula) and what we do in algebra is to study equations that can be reduced to quadratic or linear equations.