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(15x-1)(6x+1,2)=0 equation

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Numerical solution:

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The solution

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(15*x - 1)*(6*x + 6/5) = 0
$$\left(6 x + \frac{6}{5}\right) \left(15 x - 1\right) = 0$$
Detail solution
Expand the expression in the equation
$$\left(6 x + \frac{6}{5}\right) \left(15 x - 1\right) = 0$$
We get the quadratic equation
$$90 x^{2} + 12 x - \frac{6}{5} = 0$$
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
$$a = 90$$
$$b = 12$$
$$c = - \frac{6}{5}$$
, then
D = b^2 - 4 * a * c = 

(12)^2 - 4 * (90) * (-6/5) = 576

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

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

or
$$x_{1} = \frac{1}{15}$$
$$x_{2} = - \frac{1}{5}$$
Rapid solution [src]
x1 = -1/5
$$x_{1} = - \frac{1}{5}$$
x2 = 1/15
$$x_{2} = \frac{1}{15}$$
x2 = 1/15
Sum and product of roots [src]
sum
-1/5 + 1/15
$$- \frac{1}{5} + \frac{1}{15}$$
=
-2/15
$$- \frac{2}{15}$$
product
-1  
----
5*15
$$- \frac{1}{75}$$
=
-1/75
$$- \frac{1}{75}$$
-1/75
Numerical answer [src]
x1 = -0.2
x2 = 0.0666666666666667
x2 = 0.0666666666666667