Răspuns:
Explicație pas cu pas:
1.
a) 27/20 - 3/5 = 27/20 - 12/20 = 15/20 = 3/4
b) 11/14 - 7/4 = 22/28 - 49/28 = -27/28
c) -2/9 + 17/6 = -4/18 + 51/18 = 47/18
2.
2,75 = 275/100 = 11/4
1,(18) = (118 - 1)/99 = 117/99 = 13/11
11/4 - 13/11 = 121/44 - 52/44 = 69/44 = 1,56(81)
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2,(3) = (23 - 2)/9 = 21/9 = 7/3
1,16 = 116/100 = 29/25
7/3 - 29/25 = 175/75 - 87/75 = 88/75 = 1,17(3)
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1,2(7) = (127 - 12)/90 = 115/90 = 23/18
3,5 = 35/10 = 7/2
-23/18 - 7/2 = -23/18 - 63/18 = -86/18 = -43/9 = -4,(7)
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3.
2,0(6) = (206 - 20)/90 = 186/90 = 62/30= 31/15
a = 9/5 - 31/15 - 7/3 = 27/15 - 31/15 - 35/15 = - 39/15 = -13/5 = -26/10 = -2,6
opusul lui a este 2,6
