ГДЗ по Математике 6 Класс Номер 1245 Мерзляк, Полонский — Подробные Ответы

Решите уравнение:

1) \(-5x = 30\);

2) \(-08x = -5,6\);

3) \(-7x = 4\);

4) \(-6x = -8\);

5) \(\frac{2}{3}x = -\frac{3}{8}\);

6) \(40,5 : x = -9\);

7) \(-\frac{32}{63} : x = \frac{8}{21}\);

8) \(x : \frac{2}{7} = -1,4\).

1. \(-5x = 30\)
\(x = \frac{30}{-5} = -6\)

2. \(-0{,}8x = -5{,}6\)
\(x = \frac{-5{,}6}{-0{,}8} = 7\)

3. \(-7x = 4\)
\(x = \frac{4}{-7} = -\frac{4}{7}\)

4. \(-6x = -8\)
\(x = \frac{-8}{-6} = \frac{4}{3}\)

5. \(\frac{2}{3}x = -\frac{3}{8}\)
\(x = -\frac{3}{8} : \frac{2}{3} = -\frac{3}{8} \times \frac{3}{2} = -\frac{9}{16}\)

6. \(40{,}5 : x = -9\)
\(\frac{40{,}5}{x} = -9\)
\(x = \frac{40{,}5}{-9} = -4{,}5\)

7. \(-\frac{32}{63} : x = \frac{8}{21}\)
\(-\frac{32}{63} \div x = \frac{8}{21}\)
\(-\frac{32}{63} = \frac{8}{21}x\)
\(x = -\frac{32}{63} : \frac{8}{21} = -\frac{32}{63} \times \frac{21}{8} = -\frac{32 \times 21}{63 \times 8} = -\frac{672}{504} = -\frac{4}{3}\)

8. \(x : \frac{2}{7} = -1{,}4\)
\(x = -1{,}4 \times \frac{2}{7} = -0{,}4\)

1) \(-5x = 30\)

Делим обе части уравнения на \(-5\):

\[
x = \frac{30}{-5} = -6
\]

2) \(-0{,}8x = -5{,}6\)

Делим обе части на \(-0{,}8\):

\[
x = \frac{-5{,}6}{-0{,}8} = 7
\]

3) \(-7x = 4\)

Делим обе части на \(-7\):

\[
x = \frac{4}{-7} = -\frac{4}{7}
\]

4) \(-6x = -8\)

Делим обе части на \(-6\):

\[
x = \frac{-8}{-6} = \frac{8}{6} = \frac{4}{3}
\]

5) \(\frac{2}{3}x = -\frac{3}{8}\)

Делим обе части на \(\frac{2}{3}\):

\[
x = -\frac{3}{8} : \frac{2}{3} = -\frac{3}{8} \times \frac{3}{2} = -\frac{9}{16}
\]

6) \(40{,}5 : x = -9\)

Запишем деление как дробь:

\[
\frac{40{,}5}{x} = -9
\]

Домножаем обе части на \(x\):

\[
40{,}5 = -9x
\]

Делим обе части на \(-9\):

\[
x = \frac{40{,}5}{-9} = -4{,}5
\]

7) \(-\frac{32}{63} : x = \frac{8}{21}\)

Запишем деление как дробь:

\[
-\frac{32}{63} \div x = \frac{8}{21}
\]

Это значит:

\[
-\frac{32}{63} = \frac{8}{21}x
\]

Делим обе части на \(\frac{8}{21}\):

\[
x = -\frac{32}{63} : \frac{8}{21} = -\frac{32}{63} \times \frac{21}{8} = -\frac{32 \times 21}{63 \times 8}
\]

Сокращаем:

\[
-\frac{672}{504} = -\frac{4}{3}
\]

8) \(x : \frac{2}{7} = -1{,}4\)

Запишем деление как дробь:

\[
\frac{x}{\frac{2}{7}} = -1{,}4
\]

Домножаем обе части на \(\frac{2}{7}\):

\[
x = -1{,}4 \times \frac{2}{7} = -\frac{14}{10} \times \frac{2}{7} = -\frac{28}{70} = -0{,}4
\]