D(y): (x+4)(7-x)>=0
7x+28-4x-x2>=0
-x2-4x+28>=0 | : -1
x2+4x-28=0
x1=7;
x2=-4;
D(y): x>(-4)
x є -4; + ∞
D(y): (x+4)(7-x)>=0
7x+28-4x-x2>=0
-x2-4x+28>=0 | : -1
x2+4x-28=0
x1=7;
x2=-4;
D(y): x>(-4)
x є -4; + ∞