Curious Quadratic
Channel: Graham Roberts
Date: 2017-06-22

A quadratic solutions seen in the film Hidden Figures (2016). Can you solve the one a 7-year old girl does back in the 1930's?

Note: factorising a quadratic equation depends on the fact that the form is fixed. It requires only a little arithmetic and understanding negative numbers.  The rules used provide shortcuts and doubtless young Kathy did that as mental arithmetic confirmed on the board but wowing her classmates.

See https://www.bbc.co.uk/bitesize/guides/z8y9jty/revision/9 for more information.
And, a modern slip and slide method:
https://www.youtube.com/watch?v=5cHDusov5AI