Question

(1+2i) (2+5i)

I don’t know the steps to get to my answer, I know the answer is -8+9i but what are the steps?

Answer 1

Explanation:

first multiply 1 with 2+5i then multiply 2i with 2+5i and you will get

2+5i+4i+10i^2

then in the next step add 4i and 5i you will get 9i

in the next step put i^2=-1 and you will get -10

in the last step just substract 2-10 you will get -8 and 9i

and your answer will be -8+9i