Двойные неравенства сроочно !!!

1)
$1 \leq \frac{5+x}{2} \ \textless \ 2.5$
$1*2 \leq \frac{5+x}{2}*2 \ \textless \ 2.5*2$
$2\leq 5+x \ \textless \ 5$
$2-5\leq 5+x -5 \ \textless \ 5-5$
$-3 \leq x \ \textless \ 0$
$[-3;0)$

2)
$0 \ \textless \ \frac{2x+3}{5}\ \textless \ 1$
$0*5 \ \textless \ \frac{2x+3}{5}*5\ \textless \ 1*5$
$0 \ \textless \ 2x+3\ \textless \ 5$
$0 -3\ \textless \ 2x+3-3\ \textless \ 5-3$
$-3\ \textless \ 2x\ \textless \ 2$
$\frac{-3}{2} \ \textless \ \frac{2x}{2}\ \textless \ \frac{2}{2}$
$-1.5\ \textless \ x\ \textless \ 1$
$(-1.5;1)$

3)
$2.15 \ \textless \ \frac{3x-1}{4}\ \textless \ 2.6$
$2.15*4\ \textless \ \frac{3x-1}{4}*4\ \textless \ 2.6*4$
$8.6\ \textless \ 3x-1\ \textless \ 10.4$
$8.6+1\ \textless \ 3x-1+1\ \textless \ 10.4+1$
$9.6\ \textless \ 3x\ \textless \ 11.4$
$\frac{9.6}{3}\ \textless \ \frac{3x}{3}\ \textless \ \frac{11.4}{3}$
$3.2\ \textless \ x\ \textless \ 3.8$
$(3.2;3.8)$

4)
$-1 \ \textless \ \frac{3x-1}{4}\ \textless \ 2$
$-1 *4\ \textless \ \frac{3x-1}{4}*4\ \textless \ 2*4$
$-4\ \textless \ 3x-1 \textless \ 8$
$-4+1\ \textless \ 3x-1+1 \textless \ 8+1$
$-3\ \textless \ 3x \textless \ 9$
$\frac{-3}{3}\ \textless \ \frac{3x}{3} \textless \ \frac{9}{3}$
$-1\ \textless \ x \textless \ 3$
$(-1;3)$