To multiply this using FOIL:
(3+5i)(6-i)
step 1) 3•6 = 18
step 2) 3• -1i = -3i
Remember: if there is no coefficient, there is technically a 1 there so it’s easier to picture if you put that one in front of the variable.
step 3) 5i•6 = 30i
step 4) 5i• -1i= -5i^2
that turns into the expression 18-3i+30i-5i^2
then you can gather like terms (the -3i and 30i) 18+27i-5i^2
Remember that when you have and i that’s squared, it turns into -1.
So, the new expression is 18+27i-5(-1)
Remember to use order of operations and multiply first -5(-1)=5
18+27i+5
Then combine the constants (18 and 5)
The answer is: 23+27i