[tex]a) \frac{x}{12} = \frac{ \frac{7}{12} }{7} = \frac{x}{12} = \frac{1}{12} \\ x = 1[/tex]
[tex]b) \frac{ \frac{1}{5} - \frac{1}{25} }{4} = \frac{x}{75} \\ \frac{ \frac{4}{25} }{4} = \frac{x}{75} \\ \frac{1}{25} = \frac{x}{75} \\ 25x = 75 \\ x = 3[/tex]
[tex]c) \frac{3}{8} = \frac{ \frac{3}{4} + \frac{27}{4} }{x + 1} \\ \frac{3}{8} = \frac{ \frac{15}{2} }{x + 1} \\ \frac{3}{8} = \frac{15}{2(x + 1)} \\ 6(x + 1) = 120 \\ x + 1 = 20 \\ x =1 9[/tex]
[tex]d) \frac{ \frac{1}{5} + \frac{2}{9} }{2x + 1} = \frac{1}{45} \\ \frac{ \frac{19}{45} }{2x + 1} = \frac{1}{45} \\ \frac{19}{45(2x + 1)} = \frac{1}{45} \\ 45(2x + 1) = 855 \\ 2x + 1 = 19 \\ 2x = 18 \\ x = 9[/tex]
[tex]e) \frac{ {( {2}^{2} } - 2 - 1) \times {2}^{49} }{ {2}^{48} } = \frac{x}{32} \\ (4 - 2 - 1) \times 2 = \frac{x}{32} \\ 2 = \frac{x}{32} \\ x = 64[/tex]
[tex]f) \frac{x}{14 + 4} = \frac{8}{x} \\ \frac{x}{18} = \frac{8}{x} \\ {x}^{2} = 144 \\ x = 12sau - 12[/tex]
