Thực hiện phép tính: a) (3(x^2)(y^3) + 2)/(3x(y^4)) - 2/3x(y^4) b) ((x^2) - 9)/(x + 2):((x^2) + 6x + 9)/(3x + 6)
Giải thích
Hướng dẫn giải
a) \(\frac{{3{x^2}{y^3} + 2}}{{3x{y^4}}} - \frac{2}{{3x{y^4}}}\) \( = \frac{{3{x^2}{y^3} + 2 - 2}}{{3x{y^4}}}\) \( = \frac{{3{x^2}{y^3}}}{{3x{y^4}}} = \frac{x}{y}.\) | b) \(\frac{{{x^2} - 9}}{{x + 2}}:\frac{{{x^2} + 6x + 9}}{{3x + 6}}\) \( = \frac{{\left( {x - 3} \right)\left( {x + 3} \right)}}{{x + 2}}:\frac{{{{\left( {x + 3} \right)}^2}}}{{3\left( {x + 2} \right)}}\) \( = \frac{{\left( {x - 3} \right)\left( {x + 3} \right)}}{{x + 2}} \cdot \frac{{3\left( {x + 2} \right)}}{{{{\left( {x + 3} \right)}^2}}}\) \( = \frac{{3\left( {x - 3} \right)}}{{x + 3}}.\) |