Explicação passo-a-passo:
[tex]a) \frac{x}{2} - \frac{x}{4} = \frac{1}{2} \: \: \: mmc = 4[/tex]
[tex]2x - x = 2 \\ x = 2[/tex]
[tex]b) \frac{x}{2} - \frac{x}{4} = 5 \: \: \: mmc = 4[/tex]
[tex]2x - x = 20 \\ x = 20[/tex]
[tex]c) \frac{x}{5} + \frac{x}{2} = \frac{7}{10 \: \:} mmc = 10[/tex]
[tex]2x + 5x = 7 \\ 7x = 7 \\ x = \frac{7}{7} [/tex]
[tex]x = 1[/tex]
[tex]d) \frac{x}{5} + 1 = \frac{2x}{3} \: \: \: mmc = 15[/tex]
[tex]3x + 15 = 10x \\ 3x - 10x = - 15 \\ - 7x = - 15 \: \: \: \times ( - 1) \\ 7x = 15 \\ x = \frac{15}{2} \: \: ou \: \: 2.5[/tex]