Решите систему неравенств: а)2х-3>0 7х+4>0 б)3-2х<1 1,6+х<2,9

А)
$\left \{ {{2x-3\ \textgreater \ 0} \atop {7x+4\ \textgreater \ 0}} \right.$
$\left \{ {{2x\ \textgreater \ 3} \atop {7x\ \textgreater \ -4}} \right.$
$\left \{ {{x\ \textgreater \ 1,5} \atop {x\ \textgreater \ - \frac{4}{7} }} \right.$
------------(-4/7)---------(1,5)--------------
///////////////////xxxxxxxxx
Ответ: $(1,5;+$ ∞ $)$

б)
$\left \{ {{3-2x\ \textless \ 1} \atop {1,6+x\ \textless \ 2,9}} \right.$
$\left \{ {{-2x\ \textless \ 1-3} \atop {x\ \textless \ 2,9-1,6}} \right.$
$\left \{ {{-2x\ \textless \ -2} \atop {x\ \textless \ 1,3}} \right.$
$\left \{ {{x\ \textgreater \ 1} \atop {x\ \textless \ 1,3}} \right.$

-------(1)------(1,3)-----------
xxxxxxx
Ответ: $(1;1,3)$