Question

Express in terms of i: ( -12 ) − ( -3 )

Answer 1

(-12) + 1(-3) 
  -12 + -1(-3)

Multiply⇒ -1 × -3 
-12 + 3 

Then combine all the like terms ⇒ -12 + 3 

And, finally you're left with -9

So, -9 is your answer