Question 707448
(1+i)(2-4i)
Use FOIL method (first,out,in,last):
1*2=2
1*(-4i)=-4i
i*2=2i
{{{i*(-4i)= -4i^2}}}

Then simplify all answers:
{{{2-4i+2i-4i^2}}}
={{{2-2i-4i^2}}}
={{{-4i^2-2i+2}}} arrange by degree