Given the inequality:
$$\left(x^{2} - 2 x\right) + \frac{25}{2} > 0$$
To solve this inequality, we must first solve the corresponding equation:
$$\left(x^{2} - 2 x\right) + \frac{25}{2} = 0$$
Solve:
This equation is of the form
a*x^2 + b*x + c = 0
A quadratic equation can be solved
using the discriminant.
The roots of the quadratic equation:
$$x_{1} = \frac{\sqrt{D} - b}{2 a}$$
$$x_{2} = \frac{- \sqrt{D} - b}{2 a}$$
where D = b^2 - 4*a*c - it is the discriminant.
Because
$$a = 1$$
$$b = -2$$
$$c = \frac{25}{2}$$
, then
D = b^2 - 4 * a * c =
(-2)^2 - 4 * (1) * (25/2) = -46
Because D<0, then the equation
has no real roots,
but complex roots is exists.
x1 = (-b + sqrt(D)) / (2*a)
x2 = (-b - sqrt(D)) / (2*a)
or
$$x_{1} = 1 + \frac{\sqrt{46} i}{2}$$
$$x_{2} = 1 - \frac{\sqrt{46} i}{2}$$
$$x_{1} = 1 + \frac{\sqrt{46} i}{2}$$
$$x_{2} = 1 - \frac{\sqrt{46} i}{2}$$
Exclude the complex solutions:
This equation has no roots,
this inequality is executed for any x value or has no solutions
check it
subtitute random point x, for example
x0 = 0
$$\left(0^{2} - 0 \cdot 2\right) + \frac{25}{2} > 0$$
25/2 > 0
so the inequality is always executed