-45=3*(x-5)*(x+3)

Solution for -45=3*(x-5)*(x+3) equation:

-45=3(x-5)(x+3)

We move all terms to the left:

-45-(3(x-5)(x+3))=0

We multiply parentheses ..

-(3(+x^2+3x-5x-15))-45=0


We calculate terms in parentheses: -(3(+x^2+3x-5x-15)), so:

3(+x^2+3x-5x-15)

We multiply parentheses

3x^2+9x-15x-45

We add all the numbers together, and all the variables

3x^2-6x-45

Back to the equation:

-(3x^2-6x-45)


We get rid of parentheses

-3x^2+6x+45-45=0

We add all the numbers together, and all the variables

-3x^2+6x=0

a = -3; b = 6; c = 0;
Δ = b2-4ac
Δ = 62-4·(-3)·0
Δ = 36
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{36}=6$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(6)-6}{2*-3}=\frac{-12}{-6}
=+2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(6)+6}{2*-3}=\frac{0}{-6}
=0
$