Tga = sina/cosa=3,sina = 3.cosa
(2.3.cosa -cosa)/(3.cosa +3cosa)
5cosa/6cosa = 5/6, a ne rovno pí/2+k.pí
25 * х = 5*5*5*5
25*х = 625
х = 625 : 25
х= 25
__________
25*25=625
625=625
<span>13-(5x+(3x-(x-7)))=13-5х-(3х-(х-7)=13-5х-3х+(х-7)=13-5х-3х+х-7=6-7х</span>