Răspuns:
13. a) | 3/2-2/3 | + | 3/4 - 7/6 |
= | (6-4) / 6 | + | (9-14)/12|
= | 2/6 | + | -5/12|
= 2/6 + 5/12
= 9/12 = 3/4
b) | 11/5 - 5/2 | - | 7/4 - 9/5 |
= | (22- 25)/10 | - | (35-36)/20|
= |-3/10| - | -1/10 |
= 3/10 - 1/ 20
= (6-1)/20
= 5/20
= 1/4
14. a) | 3/2 - 16/9 | + | 283/90 - 1/3 |
= | (27-32)/18 | + | (283-30)/ 90 |
= | - 5/18 | + | 253/90|
= 5/18 + 253/90
= (450+4554)/ 1620
= 5004/1620
= 417/ 135
15. a) | 4- radical din 15 | = 4 - radical din 15 , ridicam totul la a 2 => 16-15 = 1
b) | radical din 26 - 5 | = radical din 26 -5 , ridicam totul la a 2 => 26-25 = 1
c) | 7- radical din 51| = radical din 51 - 7 , ridicam totul la a 2 => 51-49 =2
