(11/18-17/24)/(15/18+4/15)
Для начала порешаем в скобках
1)
(11*24)/(18*24)-(17*18)/(24*18)=264/432-306/432= -42/432= -7/72
2)
15*15/18*15+4*18/15*18=225/270+72/270=297/270=11/10=1(1/10)
3) (-7/72)/1(1/10)= (-7/72 )/(11/10)= (-7/72)*(10/11)= -70/792= -35/396