1. x²-2x-3 >/ 0
delta = b² - 4ac = 4 +12 = 16
x1 = (-b + Vdelta)/2a = (2+4)/2 = 6/2 = 3
x2 = (2-4)/2 = -2/2 = -1
A= [-1, 3] = {-1, 0, 1,2,3}
x²-36 < 0
x² < 36
x < V36
x < 6
B = (-infinit, 6) = {.....1,2,3,4,5}
a) AUB = {-infinit....5}
b) A∩B = {-1, 0,1,2,3}
2. multimea A are sigur doar 3 elemente
Din A ∩{a,b} = {a} Ambele multimi au in comun a
Fata de {b,c} A mai avea elementul a si d
Deci A= {a,d,c}
3. x²+2x-3 >/ 0
delta = 4+12 = 16
x1 = (-2+4)/2 = 2/2 = 1
x2 = (-2-4)/2 = -6/3 = -2
A = [-2,1] = {-2,-1, 0, 1}
x < 1 = > B = (-infinit, 1) = {.... -2, -1, 0}
a) AUB = (-infinit, 1]
b) A∩ B = {-2,-1, 0}
4 nu stiu
