Rut gon A 5/x+3 – 2/3-x – 3x^2-2x-9/x^2-9 lam giup mik vs 03/08/2021 Bởi Peyton Rut gon A 5/x+3 – 2/3-x – 3x^2-2x-9/x^2-9 lam giup mik vs
Đáp án: \(\frac{{ – 3x}}{{x + 3}}\) Giải thích các bước giải: \(\begin{array}{l} \frac{5}{{x + 3}} – \frac{2}{{3 – x}} – \frac{{3x^2 – 2x – 9}}{{x^2 – 9}} \\ Đkxđ:x \ne \pm 3 \\ = \frac{5}{{x + 3}} + \frac{2}{{x – 3}} – \frac{{3x^2 – 2x – 9}}{{(x – 3)(x + 3)}} \\ = \frac{{5(x – 3) + 2(x + 3) – 3x^2 + 2x + 9}}{{(x + 3)(x – 3)}} \\ = \frac{{ – 3x^2 + 9x}}{{(x + 3)(x – 3)}} \\ = \frac{{ – 3x(x – 3)}}{{(x + 3)(x – 3)}} \\ = \frac{{ – 3x}}{{x + 3}} \\ \end{array}\) Bình luận
Đáp án:
\(
\frac{{ – 3x}}{{x + 3}}
\)
Giải thích các bước giải:
\(
\begin{array}{l}
\frac{5}{{x + 3}} – \frac{2}{{3 – x}} – \frac{{3x^2 – 2x – 9}}{{x^2 – 9}} \\
Đkxđ:x \ne \pm 3 \\
= \frac{5}{{x + 3}} + \frac{2}{{x – 3}} – \frac{{3x^2 – 2x – 9}}{{(x – 3)(x + 3)}} \\
= \frac{{5(x – 3) + 2(x + 3) – 3x^2 + 2x + 9}}{{(x + 3)(x – 3)}} \\
= \frac{{ – 3x^2 + 9x}}{{(x + 3)(x – 3)}} \\
= \frac{{ – 3x(x – 3)}}{{(x + 3)(x – 3)}} \\
= \frac{{ – 3x}}{{x + 3}} \\
\end{array}
\)