Question

пж зделайте что зможыте!!!​

Answer 1

Ответ:

Объяснение:

$6)54x^{6}*\frac{1}{9}x^{2} =6x^{8}.$

Ответ: Б: 6х⁸.

$7)\\a)(\sqrt{12} +3)*(\sqrt{12}-3)=(\sqrt{12})^{2} -3^{2} =12-9=3.\\b)\frac{7x-20}{6-x} +\frac{4+3x}{x-6}=\frac{7x-20}{6-x} -\frac{4+3x}{6-x}=\frac{7x-20-4-3x}{6-x}=\\ =\frac{4x-24 }{6-x} =\frac{4*(x-6)}{6-x}=- \frac{4*(x-6)}{x-6}=-4.$

$8)\\a)(\sqrt{13} -1)^{2} +2\sqrt{13}= (\sqrt{13})^{2} -2\sqrt{13} +1+2\sqrt{13}=13+1=14.\\ b)\frac{3a}{a-3} +\frac{a+5}{6-2a} *\frac{54}{5a+a^{2} } = \frac{3a}{a-3} +\frac{a+5}{2*(3-a)}*\frac{54}{a*(5+a)}=\frac{3a}{a-3} +\frac{54*(a+5)}{2*(3-a)*a*(a+5)} =\\ =\frac{3a}{a-3} +\frac{54}{2a*(3-a)}=\frac{3a}{a-3} -\frac{54}{2a*(a-3)}=\frac{6a^{2}-54 }{2a*(a-3)}=\frac{6*(a^{2}-9) }{2a*(a-3)} =\\=\frac{3*(a-3)*(a+3)}{a*(a-3)}=\frac{3*(a+3)}{a} .$

$9)\\a)\frac{27}{x^{2}+3x } -\frac{3}{x^{2}-3x } =\frac{2}{x}\\\frac{27}{x*(x+3) } -\frac{3}{x*(x-3 )} =\frac{2}{x}\\27*(x-3)-3*(x+3)=2*(x+3)*(x-3)\\27x-81-3x-9=2x^{2} -18\\2x^{2} -24x+72=0|:2\\x^{2} -12x+36=0\\(x-6)^{2} =0\\x-6=0\\x=6.\\b)(2x+5)^{2} -3*(2x+5)-4=0\\2x+5=t\\t^{2} -3t-4=0\\D=25;\sqrt{D}=5\\ t_{1}=2x+5=4\\ 2x=-1|:2\\x_{1} =-0,5.\\t_{2}=2x+5=-1\\2x=-6|:2\\x_{2} =-3.$

Ответ: х₁=-0,5      x₂=-3.