Răspuns:
Explicație pas cu pas:
2,1(3) = (213 - 21)/90 = 192/90
1,(6) = (16 - 1)/9 = 15/9
2,1(3)/1,(6) = 192/90 : 15/9 = 192/90*9/15 = 192*9/90*15 = 32/25
√32/25 = 4√2/5
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4√2/5 - 3/√2 = 8/5√2 - 15/5√2 = -7/5√2 = -7√2/10
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1,4 = 14/10
-7√2/10 : 14/10 = -7√2/10 * 10/14 = -√2/2
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(-√2/2)^3 = -2√2/8 = -√2/4