4x − 15(2 + 3x) = 7 − 24x
4x − 30 − 45x = 7 − 24x
−41x + 24x = 7 + 30
−17x = 37
$x = -\frac{37}{17} = -2\frac{3}{17}$

$\frac{3}{4}x - 1\frac{1}{2} + \frac{1}{5}x = 1\frac{2}{3}$
$\frac{3}{4}x + \frac{1}{5}x = 1\frac{2}{3} + 1\frac{1}{2}$
$\frac{15}{20}x + \frac{4}{20}x = 1\frac{4}{6} + 1\frac{3}{6}$
$\frac{19}{20}x = 1\frac{7}{6}$
$x = \frac{13}{6} : \frac{19}{20}$
$x = \frac{13}{6} * \frac{20}{19}$
$x = \frac{13}{3} * \frac{10}{19}$
$x = \frac{130}{57} = 2\frac{16}{57}$

9y + 4(7y − 1) = 32 − 8y
9y + 28y − 4 = 32 − 8y
9y + 28y + 8y = 32 + 4
37y + 8y = 36
45y = 36
$y = \frac{36}{45}$
$y = \frac{4}{5}$

$3\frac{1}{3} - \frac{2}{3}x = 5,4 + 0,2$
$\frac{2}{3}x = 3\frac{1}{3} - 5,6$
$\frac{2}{3}x = 3\frac{1}{3} - \frac{56}{10}$
$\frac{2}{3}x = 3\frac{1}{3} - \frac{28}{5}$
$\frac{2}{3}x = 3\frac{1}{3} - 5\frac{3}{5}$
$\frac{2}{3}x = 3\frac{5}{15} - 5\frac{9}{15}$
$\frac{2}{3}x = -2\frac{4}{15}$
$x = -\frac{34}{15} : \frac{2}{3}$
$x = -\frac{34}{15} * \frac{3}{2}$
$x = -\frac{17}{5}$
$x = -3\frac{2}{5}$