ВОПРОС ЖИЗНИ И СМЕРТИ ПОМОГИТЕ!!!!!!!

Решите задачу:

$CuBKo\;1:\\1)\;\left(2\frac13-\frac{155}{27}\right):1\frac{19}{27}=\left(\frac73-\frac{155}{27}\right):\frac{46}{27}=\left(\frac{63}{27}-\frac{155}{27}\right):\frac{46}{27}=-\frac{92}{27}:\frac{46}{27}=\\=-\frac{92}{27}\cdot\frac{27}{46}=-2\\2)\;2\\3)\;\frac{\sqrt{0,25}+0,3}{\sqrt{0,81}}=\frac{0,5+0,3}{0,9}=\frac{0,8}{0,9}=\frac89\\\frac{\sqrt{0,25}+0,3}{\sqrt{0,81}}=\frac{-0,5+0,3}{0,9}=\frac{-0,2}{0,9}=-\frac29$
$\frac{\sqrt{0,25}+0,3}{\sqrt{0,81}}=\frac{0,5+0,3}{-0,9}=\frac{0,8}{-0,9}=-\frac89\\\frac{\sqrt{0,25}+0,3}{\sqrt{0,81}}=\frac{-0,5+0,3}{-0,9}=\frac{-0,2}{-0,9}=\frac29\\4)\;x^2+7x+12=0\\D=7^2-4\cdot1\cdot12=49-48=1=(1)^2\\x_{1,2}=\frac{-7\pm1}{2\cdot1}\\x_1=-4,\;\;x_2=-3$
$5)\;-x(x+2)-(x-7)(x^2+7x+49)=\\=-x^2-2x-(x^3+7x^2+49x-7x^2-49x-343)=\\=-x^2-2x-(x^3-343)=-x^3-x^2-2x+343$
$CuBKo\;2:\\1)\;x^2+2x=0\\x(x+2)=0\\x=0\;\;\;\;x+2=0\\x_1=0,\;x_2=-2\\2)\;x^2-2,42=0\\x^2=2,42\\x=\pm\sqrt{2,42}=\pm\sqrt{1,21\cdot2}=\pm1,1\sqrt2\\3)\;x^2+8=0\\x^2=-8\;-\;pew.\;HET\\4)\;13x^2=0\\x^2=0\\x=0\\5)\;x^2+5x-50=0\\D=25-4\cdot(-50)=25+200=225=(15)^2\\x_{1,2}=\frac{-5\pm15}{2}\\x_1=-10,\;x_2=5$