Question

resolver con desarrollo 9/10-(1/5+1/4)

Answer 1

1- 1/5 + 1/4 = 9/20
2- 9/10 - 9/20 = 9/20


R=9/20

Equivalencias:
1/5 = 4/20 -- 1/4 = 5/20 -- 9/10 = 18/20 

Answer 2

Ahi te va la solcuion....