# How do you simplify (4+3i)(7+i)?

Mar 26, 2016

$25 \left(1 + i\right)$

#### Explanation:

Multiply out the brackets as normal but remembering that ${i}^{2} = - 1$

Given:$\text{ } \left(4 + 3 i\right) \left(7 + i\right)$

$28 + 4 i + 21 i + 3 {i}^{2}$

$28 + 25 i + 3 \left(- 1\right)$

$25 + 25 i$

$25 \left(1 + i\right)$