-90=-10x(6x+3)

Solution for -90=-10x(6x+3) equation:

-90=-10x(6x+3)

We move all terms to the left:

-90-(-10x(6x+3))=0


We calculate terms in parentheses: -(-10x(6x+3)), so:

-10x(6x+3)

We multiply parentheses

-60x^2-30x

Back to the equation:

-(-60x^2-30x)


We get rid of parentheses

60x^2+30x-90=0

a = 60; b = 30; c = -90;
Δ = b2-4ac
Δ = 302-4·60·(-90)
Δ = 22500
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{22500}=150$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(30)-150}{2*60}=\frac{-180}{120}
=-1+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(30)+150}{2*60}=\frac{120}{120}
=1
$