tolong bantu jawab pakai cara ya kak

39. 256^2/3×3/4
256^1/2
√256=16(B)
40. 64^3/2×1/3
64^1/2
√64=8(B)
41. √9.√5-3.√16.5
3√5-3.4√5
3√5-12√5= -9√5(B)
42. √9.√6-√4.√6
=3√6-2√6=√6(A)