Đáp án:
a, x = 3/4
Giải thích các bước giải:
a, $\frac{2}{3}$x - ($\frac{-1}{2}$)² = $\frac{1}{4}$
⇒ $\frac{2}{3}$x - $\frac{1}{4}$ = $\frac{1}{4}$
⇒ $\frac{2}{3}$x =$\frac{1}{4}$ + $\frac{1}{4}$
⇒ $\frac{2}{3}$x = $\frac{1}{2}$
⇒ x = $\frac{1}{2}$ : $\frac{2}{3}$
⇒ x = $\frac{1}{2}$ . $\frac{3}{2}$
⇒ x = $\frac{3}{4}$
b, |x - $\frac{1}{4}$| + $\frac{1}{7}$ = 2$\frac{1}{7}$
⇒ |x - $\frac{1}{4}$| = 2 $\frac{1}{7}$ - $\frac{1}{7}$
⇒ |x - $\frac{1}{4}$| = 2
⇒ \(\left[ \begin{array}{l}x -\frac{1}{4} =2\\x -\frac{1}{4} =-2\end{array} \right.\)
⇒ \(\left[ \begin{array}{l}x=2,25\\x=-1,75\end{array} \right.\)
Vậy....................
c, $3^{x}$ : $11^{x}$ = 243
⇒
