Вычислим по отдельным действиям:1) 1/5*8 + 1/8*11 = (11+5)/(5*8*11) = 16/(5*8*11) = 2/(5*11);2) 1/11*14 + 1/14*17 = (17+11)/(11*14*17) = 28/(11*14*17) = 2/(11*17);3) 1/17*20 + 1/20*23 = (17+23)/(17*20*23) = 40/(17*20*23) = 2/(17*23);4) 1/23*26 + 1/26*29 = (23+29)/(23*26*29) = 52/(23*26*29) = 2/(23*29);5) 2/(5*11)+ 2/(11*17) = (2*17+2*5)/(5*11*17)=4/(5*17);6) 2/(17*23)+2/(23*29)=(2*29+2*17)/(17*23*29)=4/(17*29);7) 4/(5*17)+4/(17*29)=(4*29+4*5)/(5*17*29)=136/(5*17*29)=8/145.Ответ: 8/145.