Question

[Thầy Cao Đô]

Bài 1 (1 điểm): Thực hiện phép tính

a) $\dfrac{2y-1}{y}-\dfrac{2x+1}{x}$;

b) $\dfrac{2x}{3} \, : \, \dfrac{5}{6x^2}$.

Answer 1

[subjects]

câu a) 

\(\dfrac{2y-1}{y}-\dfrac{2x+1}{x}\\ =\dfrac{2xy-x}{xy}-\dfrac{2xy+y}{xy}\\ =\dfrac{2xy-x-2xy-y}{xy}\\ =\dfrac{-x-y}{xy}\)

câu b) 

\(\dfrac{2x}{3}:\dfrac{5}{6x^2}\\ =\dfrac{2x}{3}\cdot\dfrac{6x^2}{5}\\ =\dfrac{2x\cdot6x^2}{3\cdot5}\\ =\dfrac{12x^3}{15}=\dfrac{4x^3}{5}\)