Aflați cifra a , știind ca a) 8a<86 , b) 6a >63, c) 8a5<875 , d) 7a5<sau egal decat 775

Răspuns :

a) 8a<86
5,4,3,2,1,0

b) 6a>63
4, 5, 6, 7, 8,9

c) 8a5<875
0, 1, 2, 3, 4, 5, 6

d)7a5<sau egal cu 775
0,1,2,3,4,5,6,7
a) 80,81,82,83,84,85
a={0,1,2,3,4,5}
b) 64.65.66.67.68.69
a={4,5,6,7,8,9}
c)865,855,845,835,825,815,805
a={6,5,4,3,2,1,0}
d)775,765,755,745,735,725,715,705
a={7,6,5,4,3,2,1,0}
sper ca te-am ajutat!!!