-1.5=(3x-6)(x+5)

Solution for -1.5=(3x-6)(x+5) equation:

-1.5=(3x-6)(x+5)

We move all terms to the left:

-1.5-((3x-6)(x+5))=0

We multiply parentheses ..

-((+3x^2+15x-6x-30))-1.5=0


We calculate terms in parentheses: -((+3x^2+15x-6x-30)), so:

(+3x^2+15x-6x-30)

We get rid of parentheses

3x^2+15x-6x-30

We add all the numbers together, and all the variables

3x^2+9x-30

Back to the equation:

-(3x^2+9x-30)


We get rid of parentheses

-3x^2-9x+30-1.5=0

We add all the numbers together, and all the variables

-3x^2-9x+28.5=0

a = -3; b = -9; c = +28.5;
Δ = b2-4ac
Δ = -92-4·(-3)·28.5
Δ = 423
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{423}=\sqrt{9*47}=\sqrt{9}*\sqrt{47}=3\sqrt{47}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-9)-3\sqrt{47}}{2*-3}=\frac{9-3\sqrt{47}}{-6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-9)+3\sqrt{47}}{2*-3}=\frac{9+3\sqrt{47}}{-6}
$