5^2+log₅(3)=5²•5^log₅(3)=25•3=75
<span>сos(x-y)=1 </span>
<span>вычитаете </span>
<span>cos(x+y)=-1/2 </span>
<span>x-y=2пк </span>
<span>x+y=2п/3+ 2пm </span>
<span>x-y=2пк </span>
<span>x+y=-2п/3+2пm</span>
(k-4)!/(k-6)!=
=(k-4)(k-5)(k-6)!/(k-6)!=
=(k-4)(k-5)/1=(k-4)(k-5)=
=kˇ2-9k+20