Toán a,(2x/x+3-x-1/x-2=x-7/x^2+x-6) b,x-1/2-2x+3/3 nhỏ hơn hoặc bằng x/5+4 10/10/2021 By Parker a,(2x/x+3-x-1/x-2=x-7/x^2+x-6) b,x-1/2-2x+3/3 nhỏ hơn hoặc bằng x/5+4
Đáp án: b. \(x \ge – 15\) Giải thích các bước giải: \(\begin{array}{l}a.DK:x \ne \left\{ { – 3;2} \right\}\\\dfrac{{2x\left( {x – 2} \right) – \left( {x – 1} \right)\left( {x + 3} \right) – x + 7}}{{\left( {x – 2} \right)\left( {x + 3} \right)}} = 0\\ \to 2{x^2} – 4x – {x^2} – 2x + 3 – x + 7 = 0\\ \to {x^2} – 7x + 10 = 0\\ = {7^2} – 4.10 = 9\\ \to \left[ \begin{array}{l}x = 5\left( {TM} \right)\\x = 2\left( l \right)\end{array} \right.\\b.\dfrac{{x – 1}}{2} – \dfrac{{2x + 3}}{3} \le \dfrac{x}{5} + 4\\ \to 15x – 15 – 20x – 30 \le 6x + 4.30\\ \to 11x \ge – 165\\ \to x \ge – 15\end{array}\) Trả lời
Đáp án:
b. \(x \ge – 15\)
Giải thích các bước giải:
\(\begin{array}{l}
a.DK:x \ne \left\{ { – 3;2} \right\}\\
\dfrac{{2x\left( {x – 2} \right) – \left( {x – 1} \right)\left( {x + 3} \right) – x + 7}}{{\left( {x – 2} \right)\left( {x + 3} \right)}} = 0\\
\to 2{x^2} – 4x – {x^2} – 2x + 3 – x + 7 = 0\\
\to {x^2} – 7x + 10 = 0\\
= {7^2} – 4.10 = 9\\
\to \left[ \begin{array}{l}
x = 5\left( {TM} \right)\\
x = 2\left( l \right)
\end{array} \right.\\
b.\dfrac{{x – 1}}{2} – \dfrac{{2x + 3}}{3} \le \dfrac{x}{5} + 4\\
\to 15x – 15 – 20x – 30 \le 6x + 4.30\\
\to 11x \ge – 165\\
\to x \ge – 15
\end{array}\)