Cho \(A=\frac{1}{3} x y^{2}...

Câu hỏi: Cho \(A=\frac{1}{3} x y^{2} ; B=-\frac{3}{4} y z\). Tính A.B

A.  \(\dfrac{1}{4} x y^{3} z\)

B.  \(\dfrac{1}{3} x y^{4} z\)

C.  \(\dfrac{1}{4} x y^{4} z\)

D.  \(-\dfrac{1}{4} x y^{3} z\)