# 07.24.07

## Exercise 1.2

simple x y z = x * (y + z) simple (a - b) a b => (a - b) * (a + b) => (a * a) + (a * b) - (b * a) - (b * b) {- distributive law -} => (a * a) - (b * b) => a^{2}- b^{2}

solutions from the exercises in the book

simple x y z = x * (y + z) simple (a - b) a b => (a - b) * (a + b) => (a * a) + (a * b) - (b * a) - (b * b) {- distributive law -} => (a * a) - (b * b) => a^{2}- b^{2}