Решение смотри во вложении
Ответ
V(6 - 4х - х^2) - х = 4
V(6 - 4х - х^2) = 4 + x
{V(6 - 4х - х^2)}^2 = {4 + x}^2
6 - 4x - x^2 = 16 + 8x + x^2
2x^2 + 12x + 10 = 0
x^2 + 6x + 5 = 0
x1 = -5
<span>x2 = -1</span>
<span> x+5+(4x-6)=</span><span> x+5+4x-6 =5х -1</span>
Сos(a+b) = <span>сos a*cos b - sin a*sin b.</span><span>
Находим cos a = </span><span>√(1-(64 / 289)) = 15 / 17.
</span>sin b = √(1-(9/25)) = 4 / 5.
<span>cos(a+b) = (15 / 17)*(3 / 5) - (8 / 17)*(4 / 5) = (45-32) / 85 = 13 / 85</span>