ГДЗ по алгебре 7 класс Макарычев Задание 754

\[\boxed{\text{754\ (754).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]

\[\textbf{а)}\ 5 \cdot \left( y + \frac{2}{3} \right) - 3 = 4 \cdot \left( 3y - \frac{1}{2} \right)\]

\[5y + \frac{10}{3} - 3 = 12y - 2\]

\[5y - 12y = - 2 - \frac{1}{3}\]

\[- 7y = - \frac{7}{3}\]

\[y = - \frac{7}{3}\ :( - 7) = \frac{7}{3} \cdot \frac{1}{7}\]

\[y = \frac{1}{3}\]

\[Ответ:y = \frac{1}{3}.\]

\[\textbf{б)}\ 7 \cdot (2y - 2) - 2 \cdot (3y - 3,5) =\]

\[= 9\]

\[14y - 14 - 6y + 7 = 9\]

\[8y = 9 + 7\]

\[8y = 16\]

\[y = 2\]

\[Ответ:y = 2.\]

\[\textbf{в)}\ 21,5 \cdot (4x - 1) + 8 \cdot (12,5 - 9x) =\]

\[= 82\]

\[86x - 21,5 + 100 - 72x = 82\]

\[14x = 82 + 21,5 - 100\]

\[14x = 3,5\]

\[x = 3,5\ :14 = \frac{35}{140} = \frac{1}{4}\]

\[x = 0,25\]

\[Ответ:x = 0,25.\]

\[\textbf{г)}\ 12,5 \cdot (3x - 1) + 132,4 =\]

\[= (2,8 - 4x) \cdot 0,5\]

\[37,5x - 12,5 + 132,4 = 1,4 - 2x\]

\[37,5x + 2x = 1,4 + 12,5 - 132,4\]

\[39,5x = - 118,5\]

\[x = - 118,5\ :39,5 =\]

\[= - 1185\ :395\]

\[x = - 3\]

\[Ответ:x = - 3.\]

\[27x + 54 - 42x + 84 - 2x - 2 =\]

\[= 0\]

\[- 17x = - 136\]

\[x = 8\]

\[Ответ:x = 8.\]

\[6 \cdot (1 - 6x) - 2x - 19 =\]

\[= 4 \cdot (23 - 2x)\]

\[6 - 36x - 2x - 19 = 92 - 8x\]

\[- 38x + 8x = 92 + 13\]

\[- 30x = 105\]

\[x = 105\ :( - 30)\]

\[x = - 3,5\]

\[Ответ:x = - 3,5.\]