вот так я решила лумаю что правильно
Ответ:
Объяснение:=((6a+1)/a(a-6) +(6a-1)/a(a+6) )· (a²+1)(a²-36)/(a²+1)²=
(6a²+37a+6+6a²-37a+6)/a(a²-36) ·(a²+1)(a²-36) / (a²+1)²=
(12a²+12)/a(a²+1) =12(a²+1)/a(a²+1)=12/a.
66√3:6=11√3 -- каждое ребро тетраэдра
S=4*1/2*(11√3)²sin60°=363√3 площадь полной поверхности тетраэдра
<span>{<span><span>4x−x+2y=1</span><span>3−2x=0,2</span></span></span>
Решение.
Начальные преобразования .
<span><span>{<span><span>4x−x+2y=1</span><span>3−2x=0,2</span></span></span>
</span> <span>{<span><span>3x+2y=1</span><span>−2x+3=0,2</span></span></span><span>
{<span><span>3x+2y=1</span><span>−2x+2,8=0
</span></span></span> Решение методом подстановки.
<span><span>{<span><span>3x+2y=1</span><span>−2x+2,8=0</span></span></span>
</span> <span><span>{<span><span>3x+2y=1</span><span>x=1,4</span></span></span>
</span> <span><span>{<span><span>3<span>(<span>1,4</span>)</span>+2y=1</span><span>x=1,4</span></span></span>
</span> <span><span>{<span><span>2y+3,2=0</span><span>x=1,4</span></span></span>
</span> <span><span>{<span><span>y=−1,6</span><span>x=1,4</span></span></span>
</span> <span>{<span><span>y=−1,6</span><span>x=1,4
</span></span></span> Ответ:
<span><span>(<span><span>75</span>;−<span>85</span></span>)</span>=<span>(<span>1<span>25</span>;−1<span>35</span></span>)</span>≈(1,4;−1,6<span>)</span></span>