I answered a similar question for someone else. The absolute value of a complex number is called the modulus. This represents the DISTANCE to the origin from the point on the imaginary + real plane.
the real horizontal distance is 5 and the imaginary vertical distance is in this case 4 (from -4i) the distance is 4. So to figure out this just use the Pythagorean theorem.
5^2 + (4)^2 = c^2
25 +16 = c^2
c^2 = 41c = 6.4 So option D.
Are you sure it’s b or is it x?
Answer:
8.06
Step-by-step explanation:
Use the Pythagorean theorem:
The hypotenuse is always the slanted side, or c (x in this picture), but the other numbers can be interchanged. Doesn't matter.
Plug the numbers 4 and 7 into the formula.
Now evaluate them to get 
16+49=65
To get c, take the square root of 65
It would be .5x-5= because it says 5 less so it would be subtract 5 from half of x.
Sometimes there is no apparent way to factor it by hand /(the factors are decimals or imaginary). To try and factor these problems is nearly impossible in your head.
