Explicação passo a passo:

1/6 >>>>>>>>>>>>3,00

3/6 >>>>>>>>>>>> x

corta denominador 6

1 >>>>>>>>>>>3,00

3 >>>>>>>>>>> x

1/3 = 3/x

em cruz

1 * x = 3 * 3

x = 9,00 >>>>>resposta

b

1/6 >>>>>>>>>>>>>>>>>>>>3,00

5/6 >>>>>>>>>>>>>>>>>>> x

corta 6

1 >>>>>>>>>>>>>>>>>>>>>>>>3,00

5 >>>>>>>>>>>>>>>>>>>>>> x

1/5 = 3/x

1 * x + 5 * 3

x= 15,00 >>>>>resposta

c

1/6 >>>>>>>>>>>>>>>>>>>>>>>3,00

6/6 >>>>>>>>>>>>>>>>>>>>>> x

corta 6

1 >>>>>>>>>>>>>>>>>>>>>>> 3,00

6 >>>>>>>>>>>>>>>>>>>>>>> x

1/6 = 3/x

1* x = 6 * 3

x = 18,00 >>>>>>>>>resposta