Simplify (-3i)(-7i)(2i)

$(- 3 i) (- 7 i) (2 i)$

Step 1

Multiply $(- 3 i) (- 7 i)$ .

Multiply $- 7$ by $- 3$ .

$21 i i (2 i)$

Raise $i$ to the power of $1$ .

$21 (i^{1} i) (2 i)$

Raise $i$ to the power of $1$ .

$21 (i^{1} i^{1}) (2 i)$

Use the power rule $a^{m} a^{n} = a^{m + n}$ to combine exponents.

$21 i^{1 + 1} (2 i)$

Add $1$ and $1$ .

$21 i^{2} (2 i)$

Step 2

Rewrite $i^{2}$ as $- 1$ .

$21 \cdot - 1 (2 i)$

Step 3

Multiply $21$ by $- 1$ .

$- 21 (2 i)$

Step 4

Multiply $2$ by $- 21$ .

$- 42 i$