# How do you simplify (1- i ) - ( 3- 1) ( 3+ 1)?

Oct 4, 2017

$\left(1 - i\right) - \left(3 - 1\right) \left(3 + 1\right) = - 7$

#### Explanation:

The P in PEMDAS stands for parentheses, so do what you can in parentheses first:
You can't simplify $\left(1 - i\right)$ since $i$ isn't a real number.
$3 - 1 = 2$, and $3 + 1 = 4$, so we can rewrite the expression:
$\left(1 - i\right) - \left(3 - 1\right) \left(3 + 1\right) = \left(1 - i\right) - \left(2\right) \left(4\right)$
Multiplication and Division come before addition and subtraction in the order of operations, so multiply $2 \cdot 4 = 8$.
Now the expression is $\left(1 - i\right) - 8$. Again, we can't combine that $i$ with a real number, but we know that $1 - 8 = - 7$. So our final result is
$\left(1 - i\right) - 8 = 1 - i - 8 = - 7 - i$