Solve for: (-3i) * (6i)

Expression: $\left( -3i \right) \times \left( 6i \right)$

Multiplying a negative and a positive equals a negative: $\left( - \right) \times \left( + \right)=\left( - \right)$

$-3i \times 6i$

Calculate the product

$-18{i}^{2}$

By definition ${i}^{2}=-1$

$-18 \times \left( -1 \right)$

Any expression multiplied by $-1$ equals its opposite

$18$