\[\boxed{Вариант\ 1.}\]
\[\boxed{\mathbf{1.}}\]
\[7,3 \cdot 4,8 - 4,8 \cdot 3,3 = 4,8 \cdot (7,3 - 3,3) =\]
\[= 4,8 \cdot 4 = 19,2.\]
\[Ответ:19,2.\]
\[\boxed{\mathbf{2.}}\]
\[4\sqrt{2} = \sqrt{32};\ \ 6 = \sqrt{36};\ \ \sqrt{31};\ \ 2\sqrt{7} = \sqrt{28}.\]
\[Наибольшее\ число:6 = \sqrt{36}.\]
\[Ответ:2.\]
\[\boxed{\mathbf{3.}}\]
\[1)\ \frac{\left( c^{- 4} \right)^{3} \cdot c^{4}}{c^{- 2}} = c^{- 12} \cdot c^{6} = c^{- 6}\]
\[2)\ \frac{\left( c^{- 4} \right)^{3} \cdot c^{16}}{c} = c^{- 12} \cdot c^{15} = c^{3}\]
\[3)\ \frac{\left( c^{- 4} \right)^{3} \cdot c^{5}}{c^{- 11}} = c^{- 12} \cdot c^{16} = c^{4}\]
\[4)\ \frac{\left( c^{- 4} \right)^{3} \cdot c^{5}}{c^{11}} = c^{- 12} \cdot c^{- 6} = c^{- 18}\]
\[Ответ:3.\]
\[\boxed{\mathbf{4.}}\]
\[24 - 3x = 2 - 5 \cdot (x - 3)\]
\[24 - 3x = 2 - 5x + 15\]
\[- 3x + 5x = 17 - 24\]
\[2x = - 7\]
\[x = - 3,5.\]
\[Ответ:\ - 3,5.\]
\[\boxed{\mathbf{5.}}\]
\[А\] | \[Б\] | \[В\] |
---|---|---|
\[3\] | \[2\] | \[4\] |
\[\boxed{\mathbf{6.}}\]
\[- 7;\ - 5;\ - 3;\ldots\]
\[a_{1} = - 7;\ \ a_{2} = - 5:\]
\[d = - 5 - ( - 7) = 2.\]
\[S_{6} = \frac{2a_{1} + d(n - 1)}{2} \cdot n =\]
\[= \frac{2 \cdot ( - 7) + 2 \cdot (6 - 1)}{2} \cdot 6 =\]
\[= ( - 14 + 10) \cdot 3 = - 4 \cdot 3 = - 12.\]
\[Ответ:\ - 12.\]
\[\boxed{\mathbf{7.}}\]
\[\frac{16x^{2}}{4x - 1} + \frac{1}{1 - 4x} - 4x - 4 =\]
\[= \frac{16x^{2}}{4x - 1} - \frac{1}{4x - 1} - (4x + 4)^{\backslash 4x - 1} =\]
\[= \frac{16x^{2} - 1 - 16x^{2} - 16x + 4x + 4}{4x - 1} =\]
\[= \frac{- 12x + 3}{4x - 1} = \frac{- 3 \cdot (4x - 1)}{4x - 1} = - 3.\]
\[Ответ:\ - 3.\]
\[\boxed{\mathbf{8.}}\]
\[\frac{2x - 3}{x + 1} \geq 1^{\backslash x + 1}\]
\[\frac{2x - 3 - x - 1}{x + 1} \geq 0;\ \ \ x \neq - 1\]
\[\frac{x - 4}{x + 1} \geq 0\]
\[x < - 1;\ \ \ x \geq 4.\]
\[Ответ:4.\]
\[\boxed{\mathbf{9.}}\]
\[Ответ:3.\]
\[\boxed{\mathbf{10.}}\]
\[Ответ:4{^\circ}С.\]
\[\boxed{\mathbf{11.}}\]
\[6900\ рублей - 115\%\]
\[x\ рублей - 100\%\]
\[x = \frac{6900 \cdot 100}{115} = 60 \cdot 100 =\]
\[= 6000\ (рублей) - стоит\ диван.\]
\[Ответ:6000\ рублей.\]
\[\boxed{\mathbf{12.}}\]
\[Ответ:34.\]
\[\boxed{\mathbf{13.}}\]
\[Всего\ вариантов:\]
\[9 + 7 + 8 + 6 = 30.\]
\[Спортсменов\ из\ Китая:9.\]
\[Вероятность\ равна:\]
\[\frac{9}{30} = 0,3.\]
\[Ответ:0,3.\ \]
\[\boxed{\mathbf{14.}}\]
\[F = 1,8C + 32;\ \ F = 451{^\circ}:\]
\[451 = 1,8C + 32\]
\[1,8C = 451 - 32\]
\[1,8C = 419\]
\[C = 419\ :1,8 = 4190\ :18 =\]
\[= 232,(7) \approx 232,8{^\circ}.\]
\[Ответ:232,8{^\circ}С.\]
\[\boxed{\mathbf{15.}}\]
\[\frac{2mn}{n^{2} - m^{2}} \cdot \left( \frac{1^{\backslash n}}{m} - \frac{1^{\backslash m}}{n} \right) =\]
\[= \frac{2mn}{(n - m)(n + m)} \cdot \frac{n - m}{\text{nm}} =\]
\[= \frac{2}{n + m}\]
\[m = \sqrt{3} + 6;\ \ n = \sqrt{\left( \sqrt{3} - 2 \right)^{2}}:\]
\[\frac{2}{\left| \sqrt{3} - 2 \right| + \sqrt{3} + 6} = \frac{2}{2 - \sqrt{3} + \sqrt{3} + 6} =\]
\[= \frac{2}{8} = \frac{1}{4} = 0,25.\]
\[Ответ:0,25.\]
\[\boxed{\mathbf{16.}}\]
\[Пусть\text{\ x\ }\frac{км}{ч} - первоначальная\ \]
\[скорость\ автомобиля;\]
\[(x - 10)\ \frac{км}{ч} - скорость\ автомобиля\]
\[после\ снижения.\]
\[y\ км - расстояние\ между\ пунктами.\]
\[2\ ч + 20\ мин = 2\ ч + \frac{1}{3}\ ч = 2\frac{1}{3}\ ч = \frac{7}{3}\ ч.\]
\[Составим\ систему\ уравнений:\]
\[\left\{ \begin{matrix} y = 4x\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \\ y = 2x + (x - 10) \cdot \frac{7}{3} \\ \end{matrix} \right.\ \]
\[4x = 2x + (x - 10) \cdot \frac{7}{3}\ \ | \cdot 3\]
\[12x = 6x + (x - 10) \cdot 7\]
\[12x = 6x + 7x - 70\]
\[12 - 13x = - 70\]
\[- x = - 70\]
\[x = 70\ \left( \frac{км}{ч} \right) - первоначальная\ \]
\[скорость\ автомобиля.\]
\[Ответ:70\ \frac{км}{ч}.\]
\[\boxed{\mathbf{17.}}\]
\[y = \frac{x^{4} - 20x^{2} + 64}{(x - 2)(x + 4)} =\]
\[= \frac{(x + 4)(x - 4)(x + 2)(x - 2)}{(x - 2)(x + 4)} =\]
\[= (x - 4)(x + 2) = x^{2} - 4x + 2x - 8 =\]
\[= x^{2} - 2x - 8.\]
\[x^{4} - 20x^{2} + 64 =\]
\[= (x + 4)(x - 4)(x + 2)(x - 2)\]
\[x_{1}^{2} + x_{2}^{2} = 20;\ \ x_{1}^{2} \cdot x_{2}^{2} = 64\]
\[x_{1}^{2} = 16;\ \ \ x_{2}^{2} = 4.\]
\[y = x^{2} - 2x - 8;\ \ \ x \neq 2;\ \ x \neq - 4:\]
\[Прямая\ y = p\ имеет\ с\ графиком\ ровно\]
\[одну\ общую\ точку\ при:\]
\[p = 16;\ \]
\[p = - 8;\]
\[p = - 9.\]
\[Ответ:\ - 9;\ - 8;16.\]