-12x^2+0x+21=0

Solution for -12x^2+0x+21=0 equation:

-12x^2+0x+21=0

We add all the numbers together, and all the variables

-12x^2+x+21=0

a = -12; b = 1; c = +21;
Δ = b2-4ac
Δ = 12-4·(-12)·21
Δ = 1009
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{-(1)-\sqrt{1009}}{2*-12}=\frac{-1-\sqrt{1009}}{-24}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1)+\sqrt{1009}}{2*-12}=\frac{-1+\sqrt{1009}}{-24}
$