# How do you simplify (4 + i)(1 – 5i)?

Feb 14, 2016

9 - 19i

#### Explanation:

distribute the brackets using FOIL ( or any method you use )

hence $\left(4 + i\right) \left(1 - 5 i\right) = 4 - 20 i + i - 5 {i}^{2}$

[note : ${i}^{2} = {\left(\sqrt{-} 1\right)}^{2} = - 1$]

$s o$ 4 - 20i + i + 5 = 9 - 19i