Question

помогите, пожалуйста!!

Answer 1

$1\leq \dfrac{1-3a}2\leq 2\quad|\cdot2\\\\2\leq 1-3a\leq 4\quad|-1\\\\1\leq -3a\leq 3\quad|:(-3)\\\\-\dfrac13\geq a\geq -1\\\\-1\leq a\leq -\dfrac13$

$a\in\bigg[-1;\ -\dfrac13\bigg]$

Answer 2

Ответ:

$\displaystyle 1\leq \frac{1-3a}{2}\leq 2\\\\\\2\leq 1-3a\leq 4\\\\2-1\leq -3a\leq 4-1\\\\1\leq -3a\leq 3\\\\-3\leq 3a\leq -1\\\\-1\leq a\leq -\dfrac{1}{3}\\\\a\in \Big[-1\ ;-\frac{1}{3}\ \Big]$