Complex numbers satisfy the same rules of arithmetic as ordinary numbers, with the addition that i2=−1. The distributivity rule gives that
i(2+3i)=i2+i3i=2i+3i2=2i+3(−1)=2i−3=−3+2i
2+i3i=2i+3i2=2i+3(−1)=2i−3=−3+2i