Đáp án:
Giải thích các bước giải:
a)
$\dfrac{3}{4} + x = \dfrac{-1}{6}$
$x = \dfrac{-1}{6} - \dfrac{3}{4} $
$x = \dfrac{-11}{12}$
b)
$x - \dfrac{7}{9} = \dfrac{11}{3} $
$x = \dfrac{11}{3} + \dfrac{7}{9}$
$x = \dfrac{40}{9}$
c)
\dfrac{x+1}{2} = \dfrac{8}{x+1}
(x+1)² = 2 . 8
(x+1)² = 16
⇒ x+1 = ±4
\(\left[ \begin{array}{l}x=3\\x=-5\end{array} \right.\)
d)
$| 2x - 3 | = 7$
$2x - 3 = ±7$
\(\left[ \begin{array}{l}2x - 3=7\\2x - 3=-7\end{array} \right.\)
\(\left[ \begin{array}{l}2x=10\\2x=-4\end{array} \right.\)
\(\left[ \begin{array}{l}x=5\\x=-2\end{array} \right.\)
