# How do you simplify (1+i)(1-i)?

$2$.
We use the Identity $: \left(a + b\right) \left(a - b\right) = {a}^{2} - {b}^{2} , \mathmr{and} , {i}^{2} = - 1$.
Hence, the given Expression$= {1}^{2} - {i}^{2} = 1 - \left(- 1\right) = 1 + 1 = 2$.