Which expression is equal to −2i(−9+6i) ?
\(\begin{array}{|rcll|} \hline && -2i(-9+6i) \\ &=& 18i-12i^2 \quad & | \quad i^2 = -1 \\ &=& 18i-12(-1) \\ &=& 18i+12 \\ &=& 12 + 18i \\ \hline \end{array}\)
