Answer
$13$
Work Step by Step
Step 1: $(2-3i)(2+3i)$
Step 2: $2(2+3i)-3i(2+3i)$
Step 3: $2(2)+2(3i)-3i(2)-3i(3i)$
Step 4: $4+6i-6i-9i^{2}$
Step 5: Since $i^{2}=−1$, the expression becomes
$4+6i-6i-9(-1)$
Step 6: $4+6i-6i+9$
Step 7: $4+9+6i-6i$
Step 8: $13$
