What is -2√20-√125 in simplest radical form

√20 the prime factors are 2, 2, 5 so
-2 * √4 *√5
-2*2*√5
-4√5 is the first part ,
now for √125, use prime factorization ,
all prime factors that make up 125 is
5, 5, 5 so √125 can be separated to √25√5 and √25 = 5 so the second part is 5√5.
now -4√5 - 5√5 = -9√5.
therefore answer is -9√5