<em>cos125=cos(180-55)=-cos55</em>
<em>cos85=cos(90-5)=sin5</em>
<span><em>-cos55cos5+sin55sin5=-(cos55cos5-sin55sin5)=-(cos60)=-1/2</em></span>
(27-8а)³=19683-17496а+5184а²-512а³
8х³+у³=(2х+у)(4х²-2ху+у²)
27а³-8b³=(3-2а)(9+6а+4а)
(1+64у)³=1+192у+12288у²+262144у³
<span><span>√</span>7x-31=5</span>
<span><span>7x-31=25</span></span>
<span><span>7х=56</span></span>
<span><span>х=8</span></span>
5+х²=(х+1)(х+6)
5+х²=х²+6х+1х+6
иксы квадратные сокращаются
5-7х-6=0
-1-7х=0
-7=1
х=-1/7
Вооот, ответы, я чуть не сдох