- Xin ctlhn
a) $\frac{3}{8}$ - $\frac{1}{2}$x = 1
⇒ $\frac{1}{2}$x = $\frac{3}{8}$ - 1
⇒ $\frac{1}{2}$x = $\frac{-5}{8}$
⇒ x = $\frac{-5}{8}$ : $\frac{1}{2}$
⇒ x = $\frac{-5}{4}$
Vậy x = $\frac{-5}{4}$
b) $\frac{9}{2}$ - | x - $\frac{3}{4}$ | = $\frac{1}{2}$
⇒ | x - $\frac{3}{4}$ | = $\frac{9}{2}$ - $\frac{1}{2}$
⇒ | x - $\frac{3}{4}$ | = 4
⇒ \(\left[ \begin{array}{l} x - \frac{3}{4} = 4\\ x - \frac{3}{4} = -4\end{array} \right.\)
⇒ \(\left[ \begin{array}{l}x=4 +\frac{3}{4} \\x=-4 + \frac{3}{4}\end{array} \right.\)
⇒ \(\left[ \begin{array}{l}x=\frac{19}{4} \\x=\frac{-13}{4} \end{array} \right.\)
Vậy x ∈ { $\frac{19}{4}$ ; $\frac{-13}{4}$ }
c) x² = 25%x
⇒ x² - $\frac{1}{4}$x = 0
⇒ x. ( x - $\frac{1}{4}$ ) = 0
⇒ \(\left[ \begin{array}{l}x=0\\x=\frac{1}{4}\end{array} \right.\)
Vậy x ∈ { 0 ; $\frac{1}{4}$ }
