Explicación paso a paso:
[tex]19). \: \frac{3x}{5} - \frac{3}{4} = x - \frac{2}{5} \\ 12x - 15 = 20x - 8 \\ 12x - 20x = - 8 + 15 \\ - 8x = 7 \\ x = - \frac{7}{8} [/tex]
[tex]20). \: \frac{x}{2} + \frac{3}{4} = \frac{2x}{3} - 2 \\ 6x + 9 = 8x - 24 \\ 6x - 8x = - 24 - 9 \\ - 2x = - 33 \\ x = \frac{33}{2} [/tex]
[tex]21). \: \frac{3x}{2} - 2 = \frac{5}{4} - 3x \\ 6x - 8 = 5 - 12x \\ 6x + 12x = 5 + 8 \\ 18x = 3 \\ x = \frac{13}{18} [/tex]
[tex]22). \: \frac{3x}{5} - \frac{4}{5} = \frac{5}{3} - 2x \\ 9x - 12 = 25 - 30x \\ 9x + 30x = 25 + 12 \\ 39x = 37 \\ x = \frac{37}{39} [/tex]
