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5x^2+4x-1=0

5x^2+4x-1=0 equation

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Numerical solution:

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The solution

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5*x  + 4*x - 1 = 0
$$\left(5 x^{2} + 4 x\right) - 1 = 0$$
Detail solution
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
$$a = 5$$
$$b = 4$$
$$c = -1$$
, then
D = b^2 - 4 * a * c = 

(4)^2 - 4 * (5) * (-1) = 36

Because D > 0, then the equation has two roots.
x1 = (-b + sqrt(D)) / (2*a)

x2 = (-b - sqrt(D)) / (2*a)

or
$$x_{1} = \frac{1}{5}$$
$$x_{2} = -1$$
Vieta's Theorem
rewrite the equation
$$\left(5 x^{2} + 4 x\right) - 1 = 0$$
of
$$a x^{2} + b x + c = 0$$
as reduced quadratic equation
$$x^{2} + \frac{b x}{a} + \frac{c}{a} = 0$$
$$x^{2} + \frac{4 x}{5} - \frac{1}{5} = 0$$
$$p x + q + x^{2} = 0$$
where
$$p = \frac{b}{a}$$
$$p = \frac{4}{5}$$
$$q = \frac{c}{a}$$
$$q = - \frac{1}{5}$$
Vieta Formulas
$$x_{1} + x_{2} = - p$$
$$x_{1} x_{2} = q$$
$$x_{1} + x_{2} = - \frac{4}{5}$$
$$x_{1} x_{2} = - \frac{1}{5}$$
The graph
Rapid solution [src]
x1 = -1
$$x_{1} = -1$$
x2 = 1/5
$$x_{2} = \frac{1}{5}$$
x2 = 1/5
Sum and product of roots [src]
sum
-1 + 1/5
$$-1 + \frac{1}{5}$$
=
-4/5
$$- \frac{4}{5}$$
product
-1 
---
 5 
$$- \frac{1}{5}$$
=
-1/5
$$- \frac{1}{5}$$
-1/5
Numerical answer [src]
x1 = 0.2
x2 = -1.0
x2 = -1.0
The graph
5x^2+4x-1=0 equation