Answer:
-42+10i
Step-by-step explanation:
*start with the square roots
\sqrt{-25} \\ =5i
\sqrt{-100} \\ = 10i
*then insert values
(2+5i)(4-10i)
*Use FOIL to multiply
2x4 + 2x-10i + 5ix4 + 5ix10i
*Simplify
8-10i+20i+50i(squared)
*Add like terms
-42+10i
*( i squared = -1 )
