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5x^2+9x+4=0

5x^2+9x+4=0 equation

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Numerical solution:

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The solution

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5*x  + 9*x + 4 = 0
$$\left(5 x^{2} + 9 x\right) + 4 = 0$$
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
$$a = 5$$
$$b = 9$$
$$c = 4$$
, then
D = b^2 - 4 * a * c = 

(9)^2 - 4 * (5) * (4) = 1

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

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

or
$$x_{1} = - \frac{4}{5}$$
$$x_{2} = -1$$
Vieta's Theorem
rewrite the equation
$$\left(5 x^{2} + 9 x\right) + 4 = 0$$
of
$$a x^{2} + b x + c = 0$$
as reduced quadratic equation
$$x^{2} + \frac{b x}{a} + \frac{c}{a} = 0$$
$$x^{2} + \frac{9 x}{5} + \frac{4}{5} = 0$$
$$p x + q + x^{2} = 0$$
where
$$p = \frac{b}{a}$$
$$p = \frac{9}{5}$$
$$q = \frac{c}{a}$$
$$q = \frac{4}{5}$$
Vieta Formulas
$$x_{1} + x_{2} = - p$$
$$x_{1} x_{2} = q$$
$$x_{1} + x_{2} = - \frac{9}{5}$$
$$x_{1} x_{2} = \frac{4}{5}$$
The graph
Rapid solution [src]
x1 = -1
$$x_{1} = -1$$
x2 = -4/5
$$x_{2} = - \frac{4}{5}$$
x2 = -4/5
Sum and product of roots [src]
sum
-1 - 4/5
$$-1 - \frac{4}{5}$$
=
-9/5
$$- \frac{9}{5}$$
product
-(-4) 
------
  5   
$$- \frac{-4}{5}$$
=
4/5
$$\frac{4}{5}$$
4/5
Numerical answer [src]
x1 = -1.0
x2 = -0.8
x2 = -0.8
The graph
5x^2+9x+4=0 equation