(2+3I)(2-I)

Question

I need help in pre cal im having a hard time trying to understand the teacher.

Answer 1

i = √-1, (square root of negative one)

 

Thus, i² = -1

 

So, (2+3i)(2-i) = 4 - 2i + 6i - 3i² = 4 + 4i - 3(-1) = 7 + 4i