Question

Rezolvati,in multimea numerelor naturale,inecuatiile : a) 7x-5 mai mic sau egal2x+60 ; b)18x+256>7 inmultit(2x+103) ; c)12x+9 mai mic sau egal 4(3X+2) ; d) x+9x<73+37 ; e) 2 inmultit[10+7 inmultit (82-9 la puterea 2)]+x<2011 ; f) 41 la putere x+6 <41 la puterea 10

Answer 1

a] 7x-5≤2x+60\+5
7x≤2x+65\-2x
5x≤65\:5
x≤13
x  ∈ [0,1,2,3,......,13]

x=cu toate nr pana la 13si 13

b]18x+256>7·[2x+103]
18x+256>14x+721\ -256
18x>14x+456\ -14x
4x>456
x>114
x ∈[115,116,117.........]

c]12x+9≤4[3x+2]
12x+9≤12X+8
nu este posibil 

d]x+9x<110
10x<110\:10
x<11
x∈[0,1,2,3,4....,10]

e]2·[10+7·{82-9∧2}]+X≤2011
2·[10+7·1]+x≤2011
2·17+x≤2011
34+x≤2011\-34
x≤1977
x∈[0,1,2,3,4.........1977]

f]  41∧ x+6<41∧10
x+6<10\-6
x<4
x∈  [0,1,2,3]