You can use FOIL to find the answer.
F, first. You multiply the first number/part in each: 5x8=40
O, outside. The parts on the outside of the problem: 5(-2i)=-10i
I, inside. Product of the inside parts: 3i(8)=24i
L, last. The last parts. Opposite of first parts: 3i(-2i)=-6i^2
Add all of it together: -6i^2+14i+40
