Question

How do I solve this? (6+8i)(4-7i)
step by step??
I just need a tutor...

Answer 1

`Use:\\\\FOIL:\\(a + b)(c + d) = ac + ad + bc + bd\\\\i=√(-1)\to i^2=-1\\-----------------------\\\\(6+8i)(4-7i)=(6)(4)+(6)(-7i)+(8i)(4)+(8i)(-7i)\\\\=24-42i+32i-56i^2=24-10i-56(-1)=24-10i+56\\\\=80-10i\\\\Answer:\ \boxed{(6+8i)(4-7i)=80-10i}`