4 tia

\(\dfrac{2}{3}+\dfrac{1}{3}:\dfrac{5}{9}=\dfrac{2}{3}+\dfrac{1}{3}.\dfrac{9}{5}=\dfrac{2}{3}+\dfrac{3}{5}=\dfrac{10}{15}+\dfrac{9}{15}=\dfrac{19}{15}\)

120015

Áp dụng định lý phân giác ngoài ta có:
\(\dfrac{DB}{DC}=\dfrac{AB}{AC}\Rightarrow\dfrac{1}{2}=\dfrac{y}{16}\Rightarrow y=\dfrac{1}{2}.16\Rightarrow y=8\left(cm\right)\)

\(a,4x^2y^3.\dfrac{3}{2}x^3y^4=6x^5y^7\\ b,-2x^2y^3.5x^2y^7=-10x^4y^{10}\\ c,-6x^2y^2\left(-2xy^4\right)^2=-6x^2y^2.4x^2y^8=-24x^4y^{10}\)

:VVVVVVVV

duma hôm qua ko để ý

cần lm nx ko v?