Express in simplest a+bi form: Square root of 1b + Square root of -1b

Lets simplify 
We know 

We cannot simplify 


So a + ib form is 
Answer: -12
Work: Since -4 is in parentheses, I did -4 / 5 first. After doing the division, I had gotten -0.8. I multiplied -0.8 by 15, and had gotten -12.
12 feet squared or 3 feet squared. hopefully this helps i got 2 different answers
Answer:
323.75 km
Step-by-step explanation:
185/100 = 1.85 km per nm
1.85 * 175 = 323.75 km
No because 3 can go into 63 evenly and the denominator would be left the same.