Kết quả phép tính \(\dfrac{x^4+4x^2+5}{5x^3+5}.\dfrac{2x}{x^2+4}.\dfrac{3x^3+3}{x^4+4x^2+5}\) là
\(\dfrac{6x}{x^2+4}.\)\(\dfrac{x}{5\left(x^2+4\right)}.\)\(\dfrac{6x}{5\left(x^2+4\right)}.\)\(\dfrac{3x}{x^2+4}.\)Hướng dẫn giải:\(\dfrac{x^4+4x^2+5}{5x^3+5}.\dfrac{2x}{x^2+4}.\dfrac{3x^3+3}{x^4+4x^2+5}\)
\(=\dfrac{x^4+4x^2+5}{5\left(x^3+1\right)}.\dfrac{2x}{x^2+4}.\dfrac{3\left(x^3+1\right)}{x^4+4x^2+5}\)
\(=\dfrac{2x.3}{5\left(x^2+4\right)}=\dfrac{6x}{5\left(x^2+4\right)}.\)
