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(15y+24)(3y-0.9)=0 equation

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Numerical solution:

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The solution

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(15*y + 24)*(3*y - 9/10) = 0
$$\left(3 y - \frac{9}{10}\right) \left(15 y + 24\right) = 0$$
Detail solution
Expand the expression in the equation
$$\left(3 y - \frac{9}{10}\right) \left(15 y + 24\right) = 0$$
We get the quadratic equation
$$45 y^{2} + \frac{117 y}{2} - \frac{108}{5} = 0$$
This equation is of the form
a*y^2 + b*y + c = 0

A quadratic equation can be solved
using the discriminant.
The roots of the quadratic equation:
$$y_{1} = \frac{\sqrt{D} - b}{2 a}$$
$$y_{2} = \frac{- \sqrt{D} - b}{2 a}$$
where D = b^2 - 4*a*c - it is the discriminant.
Because
$$a = 45$$
$$b = \frac{117}{2}$$
$$c = - \frac{108}{5}$$
, then
D = b^2 - 4 * a * c = 

(117/2)^2 - 4 * (45) * (-108/5) = 29241/4

Because D > 0, then the equation has two roots.
y1 = (-b + sqrt(D)) / (2*a)

y2 = (-b - sqrt(D)) / (2*a)

or
$$y_{1} = \frac{3}{10}$$
$$y_{2} = - \frac{8}{5}$$
The graph
Sum and product of roots [src]
sum
-8/5 + 3/10
$$- \frac{8}{5} + \frac{3}{10}$$
=
-13 
----
 10 
$$- \frac{13}{10}$$
product
-8*3
----
5*10
$$- \frac{12}{25}$$
=
-12 
----
 25 
$$- \frac{12}{25}$$
-12/25
Rapid solution [src]
y1 = -8/5
$$y_{1} = - \frac{8}{5}$$
y2 = 3/10
$$y_{2} = \frac{3}{10}$$
y2 = 3/10
Numerical answer [src]
y1 = -1.6
y2 = 0.3
y2 = 0.3