y=-x^2+10x-24,
-x^2+10x-24-y=0,
D=10^2-4(-1)(-24-y)=100-96-4y=4-4y,
4-4y≥0,
-4y≥-4,
y≤1,
Ey=(-∞; 1]
или
x0=-b/(2a)=5,
y0=-5^2+10*5-24=1,
a=-1<0,
Ey=(-∞; y0]=(-∞; 1]
y=-x^2+10x-24,
-x^2+10x-24-y=0,
D=10^2-4(-1)(-24-y)=100-96-4y=4-4y,
4-4y≥0,
-4y≥-4,
y≤1,
Ey=(-∞; 1]
или
x0=-b/(2a)=5,
y0=-5^2+10*5-24=1,
a=-1<0,
Ey=(-∞; y0]=(-∞; 1]