Răspuns:
Explicație pas cu pas:
a) a = 3/4 ; b = 5/8
a + b = ²⁾3/4 + 5/8 = (6+5)/8 = 11/8
a - b = ²⁾3/4 - 5/8 = (6-5)/8 = 1/8
a·b = 11/8 ·1/8 = 11/64
b) a = 1 si 7/15 = (1·15+7)/15 = 22/15
b = 4/5
a + b = 22/15 + ³⁾4/5 = (22+12)/15 = 34/15
a - b = 22/15 - ³⁾4/5 = (22-12)/15 = 10/15
a·b = 34/15 · 10/15 = 340/225⁽⁵ = 68/45
c) a = 1 si 3/4 = (1·4+3)/4 = 7/4
b = 1 si 7/12 = (1·12+7)/12 = 19/12
a + b = ³⁾7/4 + 19/12 = (21+19)/12 = 40/12 = 10/3
a - b = ³⁾7/4 - 19/12 = (21-19)/12 = 2/12 = 1/6
a·b = 10/3 ·1/6 = 10/18⁽² = 5/9 sau
a·b = 40/12 · 2/12 = 80/144⁽¹⁶ = 5/9
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