Question

If i = −1 and a and b are non-zero real numbers, what is 1a+bi ?

Answer 1

The i you normally think of (the one = to sqrt(-1) is not the same i they are using here. They are using this i the same way you would use x = - 1 in any normal equation or relation.

1a + b(-1)
a - b is your answer <<<< answer