Giải thích các bước giải: \(\begin{array}{l}\frac{3}{{{x^2} + 6x + 9}} + \frac{5}{{{x^2} – 9}}\\ = \frac{3}{{{{(x + 3)}^2}}} + \frac{5}{{(x – 3)(x + 3)}}\\ = \frac{{3(x – 3)}}{{{{(x + 3)}^2}(x – 3)}} + \frac{{5(x + 3)}}{{(x – 3){{(x + 3)}^2}}}\\ = \frac{{3x – 9 + 5x + 15}}{{{{(x + 3)}^2}(x – 3)}} = \frac{{8x – 6}}{{{{(x + 3)}^2}(x – 3)}}\end{array}\) Bình luận
Giải thích các bước giải:
\(\begin{array}{l}
\frac{3}{{{x^2} + 6x + 9}} + \frac{5}{{{x^2} – 9}}\\
= \frac{3}{{{{(x + 3)}^2}}} + \frac{5}{{(x – 3)(x + 3)}}\\
= \frac{{3(x – 3)}}{{{{(x + 3)}^2}(x – 3)}} + \frac{{5(x + 3)}}{{(x – 3){{(x + 3)}^2}}}\\
= \frac{{3x – 9 + 5x + 15}}{{{{(x + 3)}^2}(x – 3)}} = \frac{{8x – 6}}{{{{(x + 3)}^2}(x – 3)}}
\end{array}\)