Simplify 3sqrt - 32 x^4 y^6

3 sqrt (-32) x^4 y^6

sqrt (-32) = sqrt (-1) sqrt (32) = i sqrt (32):

3 i sqrt (32) x^4 y^6

sqrt (32) = sqrt (2^5) = 2^2 sqrt (2):

3 i*2^2 sqrt (2) x^4 y^6

2^2 = 4:

3 i*4 sqrt (2) x^4 y^6

3*4 = 12:

Answer: 12 i sqrt (2) x^4 y^6