Đáp án:
B1:
a) x=8
Giải thích các bước giải:
\(\begin{array}{l}
B1:\\
1)2 + 3x = x + 18\\
\to 2x = 16\\
\to x = 8\\
3)\dfrac{x}{2} + \dfrac{{x + 1}}{4} = \dfrac{{x - 2}}{3}\\
\to 6x + 3x + 3 = 4x - 8\\
\to 5x = - 11\\
\to x = - \dfrac{{11}}{5}\\
2)\left[ \begin{array}{l}
x + 9 = 0\\
6 - 3x = 0
\end{array} \right.\\
\to \left[ \begin{array}{l}
x = - 9\\
x = 2
\end{array} \right.\\
4)DK:x \ne \pm 2\\
\dfrac{{{{\left( {x + 2} \right)}^2} - {{\left( {x - 2} \right)}^2} + 16}}{{\left( {x - 2} \right)\left( {x + 2} \right)}} = 0\\
\to {x^2} + 4x + 4 - {x^2} + 4x - 4 + 16 = 0\\
\to 8x = - 16\\
\to x = - 2(l)\\
B2:\\
a)5x - 4 < 3x - 9\\
\to 2x < - 5\\
\to x < - \dfrac{5}{2}\\
b)\dfrac{{2x - 3}}{6} + \dfrac{{x - 4}}{4} \ge \dfrac{{x - 3}}{3}\\
\to 4x - 6 + 3x - 12 \ge 4x - 12\\
\to 3x \ge 6\\
\to x \ge 2
\end{array}\)
