Question

Answer 1

Có `x/3=y/5`

Đặt \(\dfrac{x}{3}=\dfrac{y}{5}=k\Rightarrow\left\{{}\begin{matrix}x=3k\\y=5k\end{matrix}\right.\)

Thay `x=3k;y=5k` vào `M,` ta đc :

\(M=\dfrac{2\cdot3k+5k}{4\cdot3k-2\cdot5k}=\dfrac{k\cdot\left(6+5\right)}{2k\cdot\left(6-5\right)}\\ =\dfrac{11}{2\cdot1}=\dfrac{11}{2}\)

Answer 2

Có M=2⋅3k+5k4⋅3k−2⋅5k=k⋅(6+5)2k⋅(6−5)=112⋅1=112