Question

1/20÷3/10–[7/5+3/15]

Answer 1

Vamos lá.

multiplique a 1ª pelo inverso da 2ª

(1/20)/(3/10) = (1/20)*(10/3) = 10/60 = 1/6

7/5 + 3/15

3/15 = 1/5

7/5 + 1/5 = 8/5

1/6 - 8/5 =

5/30 - 48/30 = -43/30