(15x+330)(-0.25x+6)=0

Solution for (15x+330)(-0.25x+6)=0 equation:

(15x+330)(-0.25x+6)=0

We multiply parentheses ..

(+0x^2+90x+0x+1980)=0

We get rid of parentheses

0x^2+90x+0x+1980=0

We add all the numbers together, and all the variables

x^2+91x+1980=0

a = 1; b = 91; c = +1980;
Δ = b2-4ac
Δ = 912-4·1·1980
Δ = 361
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{361}=19$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(91)-19}{2*1}=\frac{-110}{2}
=-55
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(91)+19}{2*1}=\frac{-72}{2}
=-36
$