Resposta:
[tex]a) \frac{15}{4} = \frac{30}{x} [/tex]
15.x = 30 . 4
15x = 120
x = 120/15
x = 8
[tex]b) \frac{3}{5} = \frac{x}{10} [/tex]
5.x = 10 . 3
5x = 30
x = 30/5
x = 6
[tex]c) \frac{1}{x} = \frac{3}{9} [/tex]
3.x = 9 . 1
3x = 9
x = 9/3
x = 3
[tex]d) \frac{x}{15} = \frac{1}{5} [/tex]
5.x = 15 . 1
5x = 15
x = 15/5
x = 3
[tex]e) \frac{x}{9} = \frac{3}{1} [/tex]
1.x = 9 . 3
x = 27
g) ????
