1)[1/(a-b) -1/(a+b)]:[2/(a-b)]=
<span> 4х-3(х-7)=2х+15</span>
<span>4х-3х+21=2х+15</span>
<span>-Х=15-21</span>
<span>х=6</span>
Решение приложено к снимку: