Răspuns:
Explicație pas cu pas:
1+2+3+...+10 = 10*11/2 = 55
a = 1/55
1+2+3+...+11 = 11*12/2 = 66
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a = 1/55
b = 1/66
b^-1 = 1/b = 1/(1/66) = 66
a : b = 1/55 : 1/66 = 1/55*66/1 = 66/55 = 6/5
-11(a - b) = -11(1/55 - 1/66) = -11*(6/11*5*6 - 5/11*5*6) = -11*1/11*5*6 = -1/30
22*(5a - 6b) = 22*(5/55 - 6/66) = 22*(1/11 - 1/11) = 0