\(3x=10y\Leftrightarrow\frac{x}{y}=\frac{10}{3}\)

A=\(\frac{16x^2-40xy}{8x^2-24xy}=\frac{\frac{16x^2}{8xy}-\frac{40xy}{8xy}}{\frac{8x^2}{8xy}-\frac{24xy}{8xy}}=\frac{2\frac{x}{y}-5}{\frac{x}{y}-3}=\frac{2.\frac{10}{3}-5}{\frac{10}{3}-3}=\frac{\frac{5}{3}}{\frac{1}{3}}=5\)

A=\(\frac{16x^2-40xy}{8x^2-24xy}=\frac{8x(2x-5y)}{ 8x(x-3y)} =\frac{2x-5y}{x-3y} \)

\(\frac{x}{y}=\frac{10}{3}<=>10y=3x <=>y=\frac{3}{10}x \)

=>A=(\(2x-\frac{3}{2}x):(x-\frac{9}{10}x) \)

=\(\frac{1}{2}x:\frac{1}{10}x=\frac{1}{2}x.\frac{10}{x}=5 \)

sorry em mới học lớp 6 thui

phan van nam ngon thi lam coi

\(\dfrac{16x^2-40xy}{8x^2-24xy}=\dfrac{8x\left(2x-5y\right)}{8x\left(x-3y\right)}=\dfrac{2x-5y}{x-3y}\)

Có : \(y=\frac{3}{10}x\left(1\right)\)

Thay (1) và PT đc \(N=\frac{16x^2-12x^2}{8x^2-\frac{36}{5}x^2}=\frac{4x^2}{\frac{4}{5}x^2}=5\)

\(\frac{x}{y}=10\Rightarrow x=10y\)

\(M=\frac{16x^2-40xy}{8x^2-24xy}=\frac{8x\left(2x-5y\right)}{8x\left(x-3y\right)}=\frac{2x-5y}{x-3y}\)

\(=\frac{2.10y-5y}{10y-3y}=\frac{15}{7}\)