[3 - 4/5 ÷ (1-3/4) +2] x 1/3 - 2/5 ÷ 3 -1/4
* (1-3/4) = (4/4 - 3/4) = (4-3)/4 = 1/4
* 2/5÷ 3 = (2/5) x (1/3) = 2/15
[3 - 4/5 ÷ (1/4) +2] x 1/3 - 2/15 -1/4
* 4/5 ÷ 1/4 = 4/5 x 4/1 = 16/5
[ 3 - 16/5 + 2 ] x (1/3) - (2/15 + 1/4)
* 3+2 =5
* 2/15 + 1/4 = (2x4 + 15x1)/(15x4) = (8+15)/(60) = 23/60
[ 5 - 16/5] x (1/3) - (23/60)
* 5-16/5 =( 5(5) - 16) / 5 = (25 - 16)/5 = 9/5
[ 9/5] x (1/3) - (23/60)
9/15 - 23/60
4(9)/4(15) - 23/60
36/60 - 23/60
13/60 = Solucion