|x-5|=|x+2| |x-1|+|x-2|=1 Hộ mình nhé giải chi tiết nhé 13/08/2021 Bởi Genesis |x-5|=|x+2| |x-1|+|x-2|=1 Hộ mình nhé giải chi tiết nhé
Đáp án: b) \(x = \dfrac{1}{2}\) Giải thích các bước giải: \(\begin{array}{l}a)\left| {x – 5} \right| = \left| {x + 2} \right|\\ \to \left[ \begin{array}{l}x – 5 = x + 2\\x – 5 = – x – 2\end{array} \right.\\ \to \left[ \begin{array}{l} – 5 = 2\left( l \right)\\2x = 3\end{array} \right.\\ \to x = \dfrac{3}{2}\\b)\left| {x – 1} \right| + \left| {x – 2} \right| = 1\\ \to \left[ \begin{array}{l}x – 1 + x – 2 = 1\left( {DK:x \ge 2} \right)\\x – 1 – x + 2 = 1\left( {DK:2 > x \ge 1} \right)\\ – x + 1 – x + 2 = 1\left( {DK:1 > x} \right)\end{array} \right.\\ \to \left[ \begin{array}{l} – 3 = 1\left( l \right)\\1 = 1\left( {ld} \right)\\ – 2x = – 1\end{array} \right.\\ \to x = \dfrac{1}{2}\end{array}\) Bình luận
Đáp án:
b) \(x = \dfrac{1}{2}\)
Giải thích các bước giải:
\(\begin{array}{l}
a)\left| {x – 5} \right| = \left| {x + 2} \right|\\
\to \left[ \begin{array}{l}
x – 5 = x + 2\\
x – 5 = – x – 2
\end{array} \right.\\
\to \left[ \begin{array}{l}
– 5 = 2\left( l \right)\\
2x = 3
\end{array} \right.\\
\to x = \dfrac{3}{2}\\
b)\left| {x – 1} \right| + \left| {x – 2} \right| = 1\\
\to \left[ \begin{array}{l}
x – 1 + x – 2 = 1\left( {DK:x \ge 2} \right)\\
x – 1 – x + 2 = 1\left( {DK:2 > x \ge 1} \right)\\
– x + 1 – x + 2 = 1\left( {DK:1 > x} \right)
\end{array} \right.\\
\to \left[ \begin{array}{l}
– 3 = 1\left( l \right)\\
1 = 1\left( {ld} \right)\\
– 2x = – 1
\end{array} \right.\\
\to x = \dfrac{1}{2}
\end{array}\)