Mister Exam

Other calculators

2x^2+6<=0 inequation

A inequation with variable

The solution

You have entered [src]
   2         
2*x  + 6 <= 0
$$2 x^{2} + 6 \leq 0$$
2*x^2 + 6 <= 0
Detail solution
Given the inequality:
$$2 x^{2} + 6 \leq 0$$
To solve this inequality, we must first solve the corresponding equation:
$$2 x^{2} + 6 = 0$$
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
$$a = 2$$
$$b = 0$$
$$c = 6$$
, then
D = b^2 - 4 * a * c = 

(0)^2 - 4 * (2) * (6) = -48

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
$$x_{1} = \sqrt{3} i$$
$$x_{2} = - \sqrt{3} i$$
$$x_{1} = \sqrt{3} i$$
$$x_{2} = - \sqrt{3} i$$
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

$$2 \cdot 0^{2} + 6 \leq 0$$
6 <= 0

but
6 >= 0

so the inequality has no solutions
Solving inequality on a graph
Rapid solution
This inequality has no solutions