Question

Câu 3 Thực hiện phép tính::(2 điểm )         

a/                 \(\dfrac{x^2}{x+2}\) + \(\dfrac{2x}{x+2}\)        

b/                \(\dfrac{5x+4}{3x+15}\) - \(\dfrac{x-2}{x+5}\)

Answer 1

a) \(\dfrac{x^2+2x}{x+2}=\dfrac{x\left(x+2\right)}{x+2}=x\)

Answer 2

b) \(\dfrac{5x+4-3\left(x-2\right)}{3\left(x+5\right)}=\dfrac{5x+4-3x+6}{3\left(x+5\right)}=\dfrac{2x+10}{3\left(x+5\right)}=\dfrac{2\left(x+5\right)}{3\left(x+5\right)}=\dfrac{2}{3}\)

Answer 3

a) Ta có: \(\dfrac{x^2}{x+2}+\dfrac{2x}{x+2}\)

\(=\dfrac{x^2+2x}{x+2}\)

\(=\dfrac{x\left(x+2\right)}{x+2}=x\)