Реши уравнения: 4.1 a) 3x = 6

4. 1 a) $3x = 6$; $x = 6 / 3$; $x = 2$ 4. 1 б) $\frac{1}{3}x = -5$; $x = -5 \cdot 3$; $x = -15$ 4. 1 в) $-2x = 12$; $x = 12 / (-2)$; $x = -6$ 4. 1 г) $\frac{3}{7}x = 9$; $x = 9 \cdot \frac{7}{3}$; $x = \frac{9 \cdot 7}{3}$; $x = \frac{63}{3}$; $x = 21$ 4. 2 a) $4x + 20 = 0$; $4x = -20$; $x = -20 / 4$; $x = -5$ 4. 2 б) $\frac{3}{2}x - 6 = 0$; $\frac{3}{2}x = 6$; $x = 6 \cdot \frac{2}{3}$; $x = \frac{6 \cdot 2}{3}$; $x = \frac{12}{3}$; $x = 4$ 4. 3 a) $7x + 9 = 100$; $7x = 100 - 9$; $7x = 91$; $x = 91 / 7$; $x = 13$ 4. 3 б) $26x - 0,8 = 7$; $26x = 7 + 0,8$; $26x = 7,8$; $x = 7,8 / 26$; $x = 0,3$ 4. 4 a) $9 + 13x = 35 + 26x$; $13x - 26x = 35 - 9$; $-13x = 26$; $x = 26 / (-13)$; $x = -2$ 4. 4 б) $\frac{7}{9}x + 3 = \frac{2}{3}x + 5$; $\frac{7}{9}x - \frac{2}{3}x = 5 - 3$; $\frac{7}{9}x - \frac{6}{9}x = 2$; $\frac{1}{9}x = 2$; $x = 2 \cdot 9$; $x = 18$ 4. 5 a) $11x - 4x = 14$; $7x = 14$; $x = 14 / 7$; $x = 2$ 4. 5 б) $20x - 13x - 12x = 6$; $20x - 25x = 6$; $-5x = 6$; $x = 6 / (-5)$; $x = -1,2$ 4. 6 a) $\frac{5}{9}x - \frac{7}{4}x + \frac{17}{18}x = - \frac{1}{4}$; $\frac{20}{36}x - \frac{63}{36}x + \frac{34}{36}x = - \frac{9}{36}$; $\frac{20 - 63 + 34}{36}x = - \frac{9}{36}$; $\frac{-9}{36}x = - \frac{9}{36}$; $x = - \frac{9}{36} / (\frac{-9}{36})$; $x = 1$ 4. 6 б) $\frac{1}{6}x - 0,82 = \frac{3}{8}x - 1,37$; $\frac{1}{6}x - \frac{3}{8}x = -1,37 + 0,82$; $\frac{4}{24}x - \frac{9}{24}x = -0,55$; $\frac{-5}{24}x = -0,55$; $x = -0,55 / (\frac{-5}{24})$; $x = -0,55 \cdot (\frac{-24}{5})$; $x = \frac{0,55 \cdot 24}{5}$; $x = \frac{13,2}{5}$; $x = 2,64$ 4. 6 г) $0,07 - 3\frac{1}{9}x = 0,26 - x$; $0,07 - \frac{28}{9}x = 0,26 - x$; $- \frac{28}{9}x + x = 0,26 - 0,07$; $- \frac{28}{9}x + \frac{9}{9}x = 0,19$; $\frac{-19}{9}x = 0,19$; $x = 0,19 / (\frac{-19}{9})$; $x = 0,19 \cdot (\frac{-9}{19})$; $x = \frac{0,19 \cdot (-9)}{19}$; $x = \frac{-1,71}{19}$; $x = -0,09$