-24x²+38x-15=0
24x²-38x+15=0
D=1444-1440=4
x=(38-2)\2=18
x=(38+2)\2=20
Ответ: 18
y= - x²-x+9
y=f(x)
1) f(2)= - 2²-2+9=3;
f(2)=3
2) f(-3)= - (-3)²-(-3)+9= -9+3+9 = 3;
f(-3)=3
3) (k;3)
x=k;
y= 3;
3 = -k² -k +9;
k² + k - 6 =0
D=1-4·1·(-6) = 1+24 = 25 = 5²
k₁ = (-1-5)/2= -3
k₂ = (-1+5)/2= 2
k₁ = -3
k₂ = 2
<span>230+x=690-260;
230+х=430;
x=430-230;
x=200</span>