what is the product of the complex numbers (2+i) and (4+i)?

Question

what is the product of the complex numbers (2+i) and (4+i)? I need help I do not understand

Answer 1

Julia,

 

multiply them one at a time and combine

 

(2+i) * 4 = 8 +4i

 

(2+i) * i = -1 +2i

 

Then combine (add) them

 

can you finish this?

Answer 2

Use FOIL to multiply

 

(2 + i)(4 + i)

8 + 4i + 2i + i²

8 + 6i - 1

7 + 6i