-3x(x+5)=-6x-8

Solution for -3x(x+5)=-6x-8 equation:

-3x(x+5)=-6x-8

We move all terms to the left:

-3x(x+5)-(-6x-8)=0

We multiply parentheses

-3x^2-15x-(-6x-8)=0

We get rid of parentheses

-3x^2-15x+6x+8=0

We add all the numbers together, and all the variables

-3x^2-9x+8=0

a = -3; b = -9; c = +8;
Δ = b2-4ac
Δ = -92-4·(-3)·8
Δ = 177
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-9)-\sqrt{177}}{2*-3}=\frac{9-\sqrt{177}}{-6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-9)+\sqrt{177}}{2*-3}=\frac{9+\sqrt{177}}{-6}
$