1,21(32) = 1 + (2132 - 21) / 9900 = 1целая 2111/9900
- 2,3(9) = -2 - (39 - 3)/90 = -2 - 36/90 = -2целых 4/10 = - 2целых 2/5
0,(6) = 6/9 = 2/3
A²-4a+2=6
a²-4a=4
3a²-12a=12
3a²-12a-2=12-2=10
B1•q^3=80/3
-90•q^3=80/3
q^3=-80/(3•90)
q^3=-8/27
q=-2/3
b1 -90. -90
S = ---- = --------- = ----- = (90•3)/5 = 54
q–1 -2/3–1 -5/3