99x+210=3x2-15x

Solution for 99x+210=3x2-15x equation:

99x+210=3x^2-15x

We move all terms to the left:

99x+210-(3x^2-15x)=0

We get rid of parentheses

-3x^2+99x+15x+210=0

We add all the numbers together, and all the variables

-3x^2+114x+210=0

a = -3; b = 114; c = +210;
Δ = b2-4ac
Δ = 1142-4·(-3)·210
Δ = 15516
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:

$\sqrt{\Delta}=\sqrt{15516}=\sqrt{36*431}=\sqrt{36}*\sqrt{431}=6\sqrt{431}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(114)-6\sqrt{431}}{2*-3}=\frac{-114-6\sqrt{431}}{-6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(114)+6\sqrt{431}}{2*-3}=\frac{-114+6\sqrt{431}}{-6}
$