b, | $2$ - $x$ | = $2$ . $( -3 )$
| $2$ - $x$ | = $-6$
Vì x có GTTĐ nên
$2$ - $x$ = $-6$ Hoặc $2$ - $x$ = $6$
$x$ = $2$ - $-6$ $x$ = $2$ - $6$
$x$ = $8$ $x$ = $4$
Vậy x ∈ { $8$ ; $4$ }
c, ( $2$$x$ - $3$ )² = $16$
( $2$$x$ - $3$ )² = $4$²
$2$$x$ - $3$ = $4$
$2$$x$ = $4$ + $3$
$2$$x$ = $7$
$x$ = $7$ : $2$
$x$ = $3,5$
d,$\frac{x}{5}$ = $\frac{2}{5}$
⇒ $x$ . $5$ = $2$ . $5$
⇒ $x$ .$5$ = $10$
⇒ $x$ = $10$ : $5$
⇒ $x$ = $2$
-- HNN --
