Question

determinati numerele naturale care verifica relatiile: a) (x+3)-(120-70)≥50 b) (75-40)-(x+5) ≥0 c) (21-17)-(5-x)<0 d) (527-432)-(x+15)≥50

Answer 1

a)x+3-50≥50⇒x≥97⇒x ∈ {97,98,99,100,...}
b)35-x-5≥0⇒x≤30⇒x ∈{0,1,2,...,30}
c)4-5+x<0⇒x<1⇒x ∈ {0}
d)95-x-15≥50⇒80-50≥x⇒30≥x⇒x≤30⇒x ∈{0,1,2,...,30}

Answer 2

a) x + 3 - 50 ≥ 50
x ≥ 50 + 47
x ≥ 97
x≥50 => x ∈ {97, ...}
b) 35 - x - 5 ≥ 0
x ≥ 30 
c) 4 - 5 + x < 0
x < 1
d) 95 - x - 15 ≥ 50
x ≥80 - 50
x≥ 30