My question is: Find the modulus of ((15i)^4)/((-5-10i)^6)
For this would the top line just be 15^4 = 50625.
The bottom line: root 125 then to the power 6.
Please help. Thanks
well the numbers in this question are fairly easy due to nice prime factors
$\displaystyle 125 = 5^3 $
$\displaystyle 15= 5 \cdot 3 $
so your fraction is
$\displaystyle \frac{(5 \cdot 3)^4 } {(5^3)^3} \rightarrow \frac{5^4 \cdot 3^4 } {5^9} \rightarrow \frac{3^4 } {5^5} $
so this can be done fairly easily without a calculator