Explicație pas cu pas:
a) 2x+6<_ 0 => 2x<_ -6 => x<_ -3 => x€ (- infinit,-3]
6y-42<_0 => 6y<_ 42 => y<_ 7 => y € (- infinit,7]
c) x^2+5x<_0
delta = 25. x1=0/2 - imposibil
x2=-10/2= -5 => x€(- infinit,-5]
y^2-y<_ 0
delta=1. y1=2/2=1
y2=0/2 - imposibil
=> y€(-infinit,1]
d)x+2<_ 1 => x<_ -1 => x €(- infinit,-1]
y-7<_ 1 => y<_ 8. => x€ (- infinit,8]
