Решебник по алгебре 8 класс Макарычев ФГОС Задание 286

 

\[\boxed{\text{286\ (286).\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]

\[В\ порядке\ убывания:\]

\[2,065;2,056\ldots;1,(37);1,371\ldots;\ \]

\[- 0,078.\]

\(\boxed{\text{286.\ }\text{еуроки}\text{-}\text{ответы}\text{\ }\text{на}\text{\ }\text{пятёрку}}\)

Пояснение.

Решение.

\[\textbf{а)}\ |28x - 8| = ?\]

\[x = - 2,5:\]

\[\left| 28 \cdot ( - 2,5) - 8 \right| = | - 70 - 8| =\]

\[= | - 78| = 78\]

\[x = 0:\]

\[|28 \cdot 0 - 8| = |0 - 8| = | - 8| = 8\]

\[x = 4:\]

\[|28 \cdot 4 - 8| = |112 - 8| =\]

\[= |104| = 104\]

\[x = 5:\]

\[|28 \cdot 5 - 8| = |140 - 8| = 132\]

\[x = 9,5:\]

\[|28 \cdot 9,5 - 8| = |266 - 8| = 258\]

\[\textbf{б)}\ |6 - 12x| = ?\]

\[x = - 3:\]

\[x = \left| 6 - 12 \cdot ( - 3) \right| = |6 + 36| =\]

\[= 42\]

\[x = - 1:\]

\[\left| 6 - 12 \cdot ( - 1) \right| = |6 + 12| = 18\]

\[x = 0:\]

\[|6 - 12 \cdot 0| = |6 - 0| = 6\]

\[x = 1:\]

\[|6 - 12 \cdot 1| = |6 - 12| = | - 6| =\]

\[= 6\]

\[x = 4:\]

\[|6 - 12 \cdot 4| = |6 - 48| = | - 42| =\]

\[= 42\]

\[\textbf{в)}\ |x| + |x - 2| = ?\]

\[x = 0,5:\]

\[0,5 + 1,5 = 2.\]

\[x = 1:\]

\[1 + 1 = 2.\]

\[x = 1,5:\]

\[1,5 + 0,5 = 2.\]

\[x = 2:\]

\[2 + 0 = 2.\]

\[\textbf{г)}\ |y - 3| + |y + 3| = ?\]

\[y = - 6:\]

\[9 + 3 = 12.\]

\[y = - 5:\]

\[8 + 2 = 10.\]

\[y = 5:\]

\[2 + 8 = 10.\]

\[y = 6:\]

\[3 + 9 = 12.\]