Question

[Trần Bảo Hân]

Cho x > 0, b > 0; rút gọn biệu thức A= \(\dfrac{xy}{xy}-\dfrac{x-y}{y-x}.\left(\dfrac{x}{x}-\dfrac{y}{y}\right)\)

Answer 1

[Nguyễn Chơn Nhân]

ta có:

\(A=\dfrac{xy}{xy}-\dfrac{x-y}{y-x}.\left(\dfrac{x}{x}-\dfrac{y}{y}\right)\\ =1-\dfrac{x-y}{y-x}.\left(1-1\right)\\ =1-\dfrac{x-y}{y-x}.0\\ =1-0\\ =1\)

Answer 2

[Nguyễn Chơn Nhân]

ta có:

$\frac{xy}{xy}-\frac{x-y}{y-x}.\left(\frac{x}{x}-\frac{y}{y}\right)$

$\backslash (1-\backslash dfrac\{x-y\}\{y-x\}.\backslash left(1-1\backslash right)\backslash \backslash \; =1-\backslash dfrac\{x-y\}\{y-x\}.0\backslash \backslash =1-0\backslash \backslash \; =1\; \backslash )$